There was the following paragraph in the article that came under the title, “GOP and the rise of Anti-knowledge” written by Mike Lofgren in Consortiumnews.com (October 29, 2015):

“English unfortunately doesn’t have a precise word for the German “Fachidiot,” a narrowly specialized person accomplished in his own field but a blithering idiot outside it. In any case, a surgeon is basically a skilled auto mechanic who is not bothered by the sight of blood and palpitating organs. We need the surgeon’s skills on pain of agonizing death, and reward him commensurately but that does not make him a Voltaire.”

In Japanese we have a word, 専門バカ, of which literal translation is “specialist idiot” meaning exactly same as defined the above - a narrowly specialized person accomplished in his own field but a blithering idiot outside it.

I’m really curious about the absence of short descriptions of the specialist who knows nothing more than his specialty area in English like German “Fachidiot,” and Japanese "専門バカ."

Isn’t there really any short word counterpart to “Fachidiot,” specialist’s ignorance, for instance, in English?


I found "narrow-minded specialisit" as a German-to-English translation of "fachidiot" in the web site, Interglot translation dictionary.

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    When considering a "no English equivalent to a German word" we have to remember that German allows compound words to be formed pretty much at will; in English a phrase would be more likely.
    – Chris H
    Commented May 25, 2016 at 7:42
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    In Google Chrome with the Transover extension, highlight the Japanese text, and the popup shows "Professional Idiot". Idiot seems better than fool here, the Greek sense of idiot originally being "private person", a condemnation of persons insular, apolitical and uncivic.
    – agc
    Commented May 25, 2016 at 7:50
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  • @agc And for a long time at least in some jurisdictions 'idiot' is also a legal term. But what do you expect from politicians/lawmakers?
    – Pryftan
    Commented Apr 5, 2020 at 18:06

14 Answers 14


The German fachidiot does indeed fill a gap in the English lexicon, until today I might have described a highly qualified person with little to no social or practical skills as someone who could have Asperger's syndrome. People who have this condition may be very focussed and experts on one or two subjects, (source) they can become obsessed in a particular field, and seem to live in their own world.

Looking at the German Wikipedia article, my browser translated the following excerpt into comprehensible English, any emphasis is mine.


As specialist idiot (especially in Austria and specialized trottel) a is an expert called that a problem only from the perspective of its subject area knows only from his point of view (narrow-mindedness can grasp) […]. Often the Fachidiot finds it difficult to empathize with others and to supplement its limited view and expand. Further possible ways of looking at it rejects due to selective perception (selfishness , narcissism) and consequent ignorance

The above description shares some similarities with Asperger's syndrome, but labelling a person is a risky affair, and should be avoided unless you are qualified to diagnose such a disorder. In alternative, may I suggest the following:

2. extreme preoccupation with and indulgence of one's feelings, desires, etc.; egoistic self-absorption.

1. narrow-minded and subjective; unwilling to understand another viewpoint.

2. an inordinate or obsessive zeal for or interest in a single thing, idea, subject, or the like.

However, none of the above really fit with the description of a fachidiot, a "subject fool", someone who knows everything about one discipline but nothing about anything else, the Independent article, written in 1998, goes on further to describe the late Margaret Thatcher:

Despite Oxford, the Bar, and her work as an industrial chemist (when she was partly responsible for the invention of Mr Whippy ice cream), she is a woman of painfully limited interests. [...] His [Dennis Thatcher] wife has no recreations or hobbies of any sort. She tried to interest herself in Chinese porcelain, but she remains a complete philistine, and notably ill-read. Her single- mindedness has been a strength, but it takes displeasing forms.

It appears that the German term draws attention to the narrow field of interests rather than the the person's incompetency or foolishness outside their specialized area of expertise. No one would ever say that the ex-British Prime Minister was an idiot, but many would agree that she was myopic, blinkered, and a solipsist.

Lastly, Dict.CC the German English Online Dictionary par excellence, offers the following translations for fachidiot

  1. geek [esp. Am.] [coll.]
  2. nerd [coll.] [obsessive expert in a specific industry]
  3. blinkered expert [Br.]
  4. one-track expert

Note, there is no mention of idiot, fool or dunce.

All definitions from Dictionary.com

  • Comments are not for extended discussion; this conversation has been moved to chat. Commented May 28, 2016 at 18:09
  • I'm admittedly not fluent but nouns in German are capitalised so the first sentence should probably capitalise the word.
    – Pryftan
    Commented Apr 5, 2020 at 18:09

Idiot savant is probably the closest you are going to get in English:

Idiot savant: 1. <...> 2. a person who is highly knowledgeable about one subject but knows little about anything else


PS: Since we bring ngram in the game... Idiot savant vs Learned fool

Just occurred to me that given the pejorative nature of the word, the best source for this usage would be Google News and indeed it seems "idiot savant" is used regularly in English news much the same way fachidiot is in German.

** The first definition is now blanked out because it appears some people are failing to notice the second definition.

  • Comments are not for extended discussion; this conversation has been moved to chat.
    – waiwai933
    Commented May 26, 2016 at 2:40
  • The Merriam Webster definition is a bit surprising, it leaves out that the person so described is usually expected to have learning difficulties. Collins and Dictionary.com (Random House) include that part. Your typical surgeon isn't usually an idiot savant. Commented Jul 30, 2019 at 13:10

I'd call that person a one trick pony

A person or group noteworthy for only a single achievement, skill, or characteristic.


For example, "He may be an excellent welder but he's a one trick pony"

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    I think "He may be an excellent mechanic but he's a bit of a one trick pony" means he's only excellent as a mechanic because his ability to do certain very limited things well. "He may be an excellent mechanic but he's a bit of a Fachidiot" on the other hand means he's an excellent mechanic, but has no interests or skills outside of mechanics, or applies a mechanic's approach to everything else. Commented May 25, 2016 at 16:20
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    As native German speaker, it comes quite close. A "Fachidiot" is very good at one complete subject, so it's a bit more than just "one trick". Actually, I wouldn't call an excellent mechanic a "one trick pony" because being an excellent mechanic is also more than "one trick" in my opinion. I would say "He's brilliant at fixing car exhausts, but he is a bit of a one trick pony".
    – gnasher729
    Commented May 27, 2016 at 13:16
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    Someone knowing Everything about Every programming language is not a one trick pony, but definitely a "Fachidiot" Commented May 28, 2016 at 16:49
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    As a German, I do not understand that "Fachidiot" requires to be skilled. He just knows one domain (and does not necessarily stand out), but isn't able to shift his perspective out of this domain. Commented May 29, 2016 at 15:22
  • "thinking inside the box" as I often say about such people Commented May 30, 2016 at 9:20

A monomath.

The opposite of a polymath:

A person with an extensive knowledge of a single subject or field, but little knowledge of others.

Definition from Wiktionary.com

Example usage:

In the last analysis, the campus is a place where one goes for broke, or goes for nothing. It is not a refuge for self-indulgent monomaths to channelize their aggressions within a community of colleagues and students.

Source: 1960, National Review, Volume 8, page 52

  • I do think that monomath is a great fit on paper, though I feel like it only implies ignorance of others, whereas fachidiot or 専門バカ could imply more of an ignorance of a person's own ignorance in other subjects. (Though I am less familiar with the Japanese word.) Commented May 28, 2016 at 19:15
  • Sounds like this should be the accepted answer. :) Commented May 29, 2016 at 18:56

Learned fool has a fair number of Ngram hits.

None are so surely caught, when they are catch'd,
As wit turn'd fool: folly, in wisdom hatch'd,
Hath wisdom's warrant and the help of school
And wit's own grace to grace a learned fool.

  • Shakespeare, Love's Labours Lost | Act 5, Scene 2

A rarely used French/Greek import:

morosoph (Noun) (obsolete) A philosophical or learned fool.

Urquhart translated Rabelais, and for morosophe, came up with morosoph. Perhaps the only usage in English, (last sentence):

He says you are a fool. And what kind of fool? A mad fool, who in your old age would enslave yourself to the bondage of matrimony, and shut your pleasures up within a wedlock whose key some ruffian carries in his codpiece. He says furthermore, Beware of the monk. Upon mine honour, it gives me in my mind that you will be cuckolded by a monk. Nay, I will engage mine honour, which is the most precious pawn I could have in my possession although I were sole and peaceable dominator over all Europe, Asia, and Africa, that, if you marry, you will surely be one of the horned brotherhood of Vulcan. Hereby may you perceive how much I do attribute to the wise foolery of our morosoph Triboulet.
-- Gargantua and Pantagruel, Book 3, Chapter XLVI

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    More common than "morosoph" is "sophomore." Unfortunately, the sense of "someone in the second year of a four year program" overwhelms the "wise fool" sense.
    – jejorda2
    Commented May 25, 2016 at 12:22
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    @jejorda2 But sophomore doesn't mean the same thing as morosoph. Even the adjective sophomoric doesn't have any savant connotation.
    – Kimball
    Commented May 25, 2016 at 15:03

At the risk of jeopardizing everyone's productivity, I should point out that TVtropes has a trope called Genius Ditz which matches pretty closely the definition of fachidiot.


It appears the is no specific term for fachidiot in English. Expressions that may suggest a similar meaning are "narrow-minded specialist" or "one-track specialist" as suggested in the following extracts:

The following definition, though from an unknown user, is very interesting:

Definition of fachidiot:

  • Noun. A derogatory term for a one-track specialist who is an expert in his field, but takes a blinkered approach to multi-faceted problems. Additional Information

  • The word originates from the German but there is no suitable translation into English. A "one-track specialist" is not quite right because you would not call someone like that an "idiot". The "fach" comes from the German for "subject". Example: "Despite being an expert in horticulture, the manager came across as something of a fachidiot when dealing with translation issues."

From: Word of the Month: Der Fachidiot

  • A Fach is a compartment in a larger container or piece of furniture. In a more figurative sense, the word denotes a specific area of expertise, often acquired through a course of study devoted to this particular field (civil engineering is an example). In the performing arts, Fach denotes the vocal range and related specialization of a singer (for example, lyrical soprano or Heldentenor) or the type of role an actor is particularly suited for (for example, action hero or ingénue).

  • An Idiot in German is the same as an idiot in English. In combination with Fach, we get a Fachidiot, a person totally focused on or only interested in his special area of expertise while remaining clueless with regard to anything outside that area. Fachidiotin is the female form, but I've heard the masculine form applied to persons of either sex.

From: 4 German words we should all use: Fachidiot,

  • An extreme specialist who only knows about their field, and doesn’t know or care about what happens around them

  • Onomatopoeia is a wonderful thing. Not only is it virtually unspellable but it allows English-speaking readers of this blog to quickly grasp the meaning of Fachidiot. It sounds like what it is, but the actual literal translation is “subject idiot“. It is someone who knows a lot about a particular field, in a similar way to a one-track specialist. But they are an idiot because a one-track specialist still notices what is going on around him. A Fachidiot simply doesn’t.

    • “…the exact opposite of a systems thinker, a person who divorces the context and consequences from individual actions.[…] so concentrated on the means they don’t even notice the ends”
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    I think this is the closest answer. There is no common phrase that means anything like Fachidiot, so you simply need to construct a phrase or sentence that best conveys your intent. Commented May 26, 2016 at 15:05

Back in the day..."Educated Idiot" was very common in usage.

  • I like it and I upvoted because I was also tempted to suggest it, but I wonder if it's quite the right tone. Typically, an educated idiot is completely useless, in or out of his field. Commented May 26, 2016 at 15:46

Tunnel vision can apply to several conditions literally or figuratively related to narrowness of acuity. Here is the entry for the term in Merriam-Webster's Eleventh Collegiate Dictionary (2003):

tunnel vision n (ca. 1942) 1 : constriction of the visual field resulting in loss of peripheral vision 2 : extreme narrowness of viewpoint : NARROWMINDEDNESS; also, single-minded concentration on one objective

As applied to your question, tunnel vision suggests a powerful, sustained ability to focus on the one thing or the few things that the person most cares about, but also very limited interest in things that fall outside the scope of the person's chief concerns and a lack of competence to judge such things.

Since there is no widely used form of the noun to describe a person with tunnel vision (along the lines of tunnel visionary), we normally say that such a person "suffers from tunnel vision" or "is afflicted by tunnel vision" or more simply "has tunnel vision."


The caricature of the absent minded professor may be used figuratively as well as literally.

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    "Absent minded professor" seems too kind here. He's no idiot, he is simply not paying attention.
    – Sylver
    Commented May 25, 2016 at 8:28
  • @Sylverdrag you might be right, but some examples I've met could probably, on a bad day, convince you otherwise.
    – Chris H
    Commented May 25, 2016 at 9:17



  1. noting or pertaining to a person who criticizes, judges, or gives advice outside the area of his or her expertise:
    The play provides a classic, simplistic portrayal of an ultracrepidarian mother-in-law.


  1. an ultracrepidarian person.


This is a very uncommon word, however.

There are more references at Wikipedia under Ultracrepidarianism and Sutor, ne ultra crepidam:

Sutor, ne ultra crepidam is a Latin expression meaning literally "Shoemaker, not beyond the shoe", used to warn people to avoid passing judgment beyond their expertise. Its origin is set down in Pliny the Elder's Naturalis Historia [XXXV, 85[1] (Loeb IX, 323–325)] where he records that a shoemaker (sutor) had approached the painter Apelles of Kos to point out a defect in the artist's rendition of a sandal (crepida from Greek krepis), which Apelles duly corrected. Encouraged by this, the shoemaker then began to enlarge on other defects he considered present in the painting, at which point Apelles advised him that ne supra crepidam sutor iudicaret[1] (a shoemaker should not judge beyond the shoe),[1] which advice, Pliny observed, had become a proverbial saying.

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    It's extremely uncommon and is totally unrelated to the OP's request.
    – Mari-Lou A
    Commented May 25, 2016 at 7:42
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    +1, not a bad try, but the term lacks the notion that the person is particularly competent in his own specialized field, and it also doesn't specify that he is an idiot in general - merely that he gives unsolicited advice in fields he isn't expert in. Take your shoemaker: there is no mention that he was a particularly good shoemaker, just that he was one. And he was overeager to offer his opinion. Doesn't make him an idiot.
    – Sylver
    Commented May 25, 2016 at 8:20
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    @Sylverdrag, well, the shoemaker was sufficiently expert to point out the defect. A fachidiot cannot be an idiot in general. They just have to be an idiot in certain areas outside of their field. Ben Carson, the alleged fachidiot from the OP's article cannot be an idiot in general. It's just not possible to become a neurosurgeon and be an idiot in general.
    – dangph
    Commented May 25, 2016 at 8:34
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    an ultracrepidarian means someone who criticises an expert in a field in which they themselves have no knowledge. It's like me criticising Lionel Messi on how he scored a goal.
    – Mari-Lou A
    Commented May 25, 2016 at 8:58
  • @Mari-LouA, your definition doesn't match the one I posted above. Where did you get it from?
    – dangph
    Commented May 25, 2016 at 9:57

"Professional idiot" is the phrase closest to the German one. Both are related to the French term deformation professionelle .

  • At least in Dutch beroepsdeformatie seems to me to mean more a rather odd but not necessarily narrow way of looking at or doing things resulting from ones profession.
    – PJTraill
    Commented May 27, 2016 at 2:21
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    I'd read "professional idiot" as someone who is so stupid, he or she isn't just an idiot, he or she must be a professional at it.
    – gnasher729
    Commented May 27, 2016 at 13:25
  • Or in the same way as a "professional Elvis". Those readings are possible but I have heard the phrase used mostly (indeed, only) in line with the German and French expressions. @gnasher729
    – zyx
    Commented May 29, 2016 at 19:21

Nerd is used like this, when it is used as a compound like "computer nerd".

Merrian-Webster defines "nerd" it as:

an unstylish, unattractive, or socially inept person; especially : one slavishly devoted to intellectual or academic pursuits

Which is a description that also fits Fachidiot.

But watch out: "nerd" used by itself is about the social ineptness only. It's adding a subject to it that puts the emphasis on the devotion to that subject.

A consultant at work last week described himself as a "QA nerd" because he likes to spend his free time arguing about the meaning of obtuse non-required paragraphs in EU directives on medical devices. Fachidiot specifically points to that enthusiasm for one subject without mentioning what the subject is.

  • This is the best answer, though they still are not quite the same. Someone earning money with line work in a factory,spending every free minute on playing chess is definitely a nerd, but not a 'Fachidiot'. Actually in Dutch, the word English nerd is currently repulsing the native Dutch word vakidioot. Commented May 28, 2016 at 17:04
  • Good point, Fachidiot also means that the subject he is a nerd of is also his profession. Commented May 28, 2016 at 20:33
  • Fachidiot is derogatory, and implies a narrow specialization, while nerd often implies a rather wide list of interests. People will very rarely refer to themselves as "Fachidiot", unless they are seriously depressed. "QA Nerd" points to the presence of QA skills/interest, while "QA Fachidiot" points to the absence of anything but QA skills.
    – Peter
    Commented May 29, 2016 at 0:15

Book-smart is close to what you said. It means

having a lot of academic knowledge learned from books and studying, but not necessarily knowing much about people and living in the real world

from the Oxford Dictionary of Learners.

Street-smart or streetwise is roughly the opposite of book-smart, with the change being from academic to real life.

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