If I have a friend that spreads their interests too thin, gathering a large body of superficial knowledge related to many topics, I'd probably use the phrase "jack of all trades, master of none" to describe them.

Are there any phrases or idioms to describe the opposite? Someone suffering from an extreme overspecialisation, who is so singular in their expertise it perhaps damages effectiveness?

  • 5
    +1, especially for reminding me of the tale of the student (a Wahoo, I believe) with 4 Fs and one D- who justified his grades to his parents with: “Folks, it was simply a case of concentrating too much time and energy on one subject.”
    – Papa Poule
    Commented Mar 12, 2016 at 1:49
  • There are professionals that are overspecialized but could not be referred to as any of the below. I'm not sure if you are describing a mental illness here or not. Niche players are some of the highest paid out there. I wonder if maybe you are describing a "fan".
    – user116032
    Commented Mar 12, 2016 at 17:37
  • youtube.com/watch?v=qXD9HnrNrvk
    – hb20007
    Commented Jul 17, 2021 at 19:09

10 Answers 10


A one-trick pony would be appropriate here. Merriam-Webster defines it as:

someone or something that is skilled in only one area

  • 1
    That is a great answer, I can't believe I forgot one-trick pony.
    – Kanga_Roo
    Commented Mar 12, 2016 at 13:48

A person who knows everything about nothing

The following quote is attributed to Konrad Lorenz

Philosophers are people who know less and less about more and more, until they know nothing about everything. Scientists are people who know more and more about less and less, until they know everything about nothing.

Example: Ask him about the mating habits of the coelacnanth, and he will tell you everything there is to know, but he has no other topic of conversation, and is never invited anywhere.

  • That's the quote I immediately thought of as well. ;-)
    – Jim
    Commented Mar 12, 2016 at 4:08
  • A Zen master would quip, "Nothing (as in, the void) is everything"
    – ottodidakt
    Commented Mar 13, 2016 at 15:53


have a one-track mind

Fig. to think entirely or almost entirely about one subject. Adolescent boys often have one-track minds. All they're interested in is the opposite sex. Bob has a one-track mind. He can only talk about football.

McGraw-Hill Dictionary of American Idioms and Phrasal Verbs

He has a one-track mind. All he ever talks about is trains and railroads. YourDictionary

Most folks have a one-track mind, and I even want to say, a "single-minded obsession" about "note-taking".

From the standpoint of productivity, "note taking" is just a very small part of the information gathering equation.

Most folks don't know there is another important part, and that's, "note-making." Quora

have blinders on/be wearing blinders

Blinders are coverings placed over a horse's eyes which prevent the horse from seeing anything that isn't straight ahead. When wearing blinders, the horse can't see anything to the sides. This helps prevent a horse from being scared by things it can't see.

The idea is that if you're wearing blinders, you have a very narrow view of things, and you aren't aware of everything that's happening around you. If I tell you to take your blinders off, I'm really telling you to look at everything around you and make an informed decision based on all the information available, instead of just making decisions based upon what you know by only looking at a small part of the problem.


Not to be able to see the big picture

the big picture also the whole picture

the most important facts about a situation and the effects that it has on other things Melissa's opinions don't take the big picture into account. Usage notes: often used after look at: When you look at the big picture, a slight increase in unemployment is not significant.

Cambridge Dictionary of American Idioms

be sitting too close to the screen to [take in/see/get/grasp] the whole picture

WordReference forums

be looking through the wrong end of the telescope


There is a phrase in the weeds (and often lost in the weeds) that means

(idiomatic) Immersed or entangled in details or complexities.


Similarly can't see the forest for the trees

to be ​unable to ​understand a ​situation ​clearly because you are too ​involved in it

Cambridge Dictionaries Online


Sounds like such a person is someone who is on the verge of “Specializing Themselves Right Out Of A Job” as per the title of the linked article from ‘fastcompany[dot]com’.

In paragraph 11 of that article there’s an interesting quote from Carter Phipps, the author of the book ‘Evolutionaries' about how the “cacophony of fact overload” can lead to “miss[ing] the big picture” and which might capture somewhat the notion that you’re after:

"We are data rich and meaning poor."


He has adopted a stovepipe approach (or mentality)

In engineering and computing,"stovepipe system" is a pejorative term for a system that has the potential to share data or functionality with other systems but which does not. The term evokes the image of stovepipes rising above buildings, each functioning individually. -- Wikipedia.  


I think you can describe this person as a monomaniac:

  • person with exaggerated or obsessive enthusiasm for or preoccupation with one thing.


  • I was going to post with crippling overspecialization (from TV Tropes) or laser-focus (UrbanDictionary) but I think you have me beaten on this one Josh. Commented Mar 11, 2016 at 21:25
  • 2
    That should be mono-maniac. A mom-o-maniac sounds like something different altogether.
    – Lawrence
    Commented Mar 12, 2016 at 2:44


: a person who is very interested in and knows a lot about a particular field or activity


You could pejoratively state that they were an idiot savant, which is an individual of extensive knowledge in a specialized area who lacks general intelligence. Merriam-Webster's online dictionary gives this as its second definition of idiot savant:

a person who is highly knowledgeable about one subject but knows little about anything else

You could also call them a boffin, which is a British slang that is often used in a similar manor, depending on their area of interest. Oxford Dictionaries online formally defines boffin as follows:

1 a person engaged in scientific or technical research: 'a computer boffin' 1.1 a person with knowledge or a skill considered to be complex, arcane, and difficult: 'he had a reputation as a tax boffin, a learned lawyer'

  • Hello, Autumn. Please add citations (and links, if possible) to the definitions that you quote in your answer. Thanks!
    – Sven Yargs
    Commented Mar 12, 2016 at 19:23
  • I added citations to the sources of the language quoted in your answers and links to the Web pages where they appear. It's important to cite the sources of quoted language in an answer; neglecting to do so results in a form of plagiarism.
    – Sven Yargs
    Commented Mar 15, 2016 at 19:12

Yes, The phrase "a jack of all trades but a master of none", is a corruption of the phrase "a jack of all trades but a master of none is still better than a master of one".


  • This doesn't answer the question
    – AndyT
    Commented Jul 26, 2017 at 15:02

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