i.e. is the comma to signify the boundary between the instruction and the recipient of it (that is to say, "Hey, stupid! Keep it simple"), or is it serving the function of an "and" (as is sometimes used in US English but rare in British).

  • 7
    Can you explain why you think that the second reading (comma means and) is a viable candidate for a reasonable interpretation of this saying (so that an argument is needed to rule it out)? To me, and I suppose a fair number of other people, this reading appears to be a non-starter (what would it be to keep something stupid and why would it be a good thing?). It would probably make the page more useful to those who come to it in the future, if you could elaborate on the matter.
    – jsw29
    May 22 at 22:04
  • 4
    @jsw29 Not so silly a doubt if it comes from a non-native English speaker (maybe this question should have been asked on English Learner SE). In some languages that comma can be interpreted as an "and". May 22 at 22:37
  • 4
    @LorenzoDonatisupportUkraine comma can be interpreted as "and" in English too and I think the question is a great one. May 23 at 8:39
  • 7
    @jsw29 I had refrained from providing my own opinion on the subject to avoid bias, but now that there are a few answers already... I always believed the first reading to be the case, but recently I saw someone represent KISS as "Keep it simple and stupid". It seemed a ridiculous interpretation but I thought best to Google before correcting them, and found a few more examples of people using that interpretation (mainly in the software development sector). There didn't seem to be any definitive proof one way or the other.
    – Chris A
    May 23 at 9:26
  • 8
    Of interest, perhaps: the version I first encountered (early 2000s, probably) was "Keep it stupid simple," where "stupid" is acting adverbially, modifying "simple": "Keep it stupidly [i.e. ridiculously] simple." Probably another "domesticated" version.
    – DLosc
    May 23 at 15:27

8 Answers 8


One thing to note is that the Wikipedia article on the subject is a bit specious:

First seen partly in American English by at least 1938 . . . the variant “Keep it Short and Simple” is attested from a 1938 issue of the Minneapolis Star.

Partly? Very partly; there is no sign of an acronym at play — no discernible throughline to KISS, no sign of “variation.”

A quick search of Google Books does indeed turn up keep it simple, stupid under the item Constitutionality of the General Accounting Office (1938), but one need only scroll into the document about 20 pages to see that it actually appears in a 1996 hearing of the Committee on Government Reform and Oversight.

I can find the phrase in print as early as 1961, in a Popular Mechanics column titled “Sidelights from the Pentagon”:

PROJECT KISS is a current Navy program which stands for, not the old social pastime, but for a new slogan, “Keep It Simple, Stupid!” It’s a reminder that simple design of weapons systems increases reliability and cuts costs.

By the early 60s, it seems the term was “old” — in common usage. This is from Five Years to Freedom — The True Story of a Vietnam POW (originally published in 1971), wherein the author recounts a 1964 experience of his:

The old “KISS” formula, “Keep it simple, stupid,” served as my guide as I built the biography which would allow me to deny knowledge of the areas they have displayed an interest in.

With or without a comma, none of this particularly proves whether stupid was meant as a form of direct address or not (I doubt that generals and engineers think much about the subtleties of punctuation).

But if simple is good here, then simple is smart — not stupid. That would leave — you (the addressee) as the primary candidate . . .

  • 6
    As an American English speaker, I never thought of "stupid" as a second adjective. Nobody ever says "Keep it simple, stupid!" because you did something smart. It is usually used to admonish someone for over-complicating something. It's also a bit sarcastic. I hear "simple" and "stupid" being used similarly, implying "simple" is "stupid", but this particular usage is also a play on words. Keeping it simple is smart, and the person being addressed is therefore stupid for making something overly complex. May 23 at 20:58
  • 2
    The quotation from Popular Mechanics does not say that the slogan KISS is "old". It implies kissing is an old social pastime. The slogan is specifically characterized as new. I'm not sure I believe James Rowe when he says it's an old formula.
    – verbose
    May 24 at 7:12
  • @verbose — I am quoting Rowe — not Popular Mechanics — on “old.” You can believe him or not. Aside: His KISS is the earliest example at Green’s Dictionary of Slang. May 24 at 13:57
  • I know you were quoting Rowe, I was merely pointing out that ten years before Rowe, Popular Mechanics was citing it as new rather than old. The fact that Green's Dictionary has Rowe as its earliest example doesn't exactly bolster the case that the phrase was "old" by the time Rowe mentions it, does it? Perhaps it's "old" for Rowe in the sense that slang does age pretty quickly; nobody says "derp" any more, and it was all the rage a decade ago
    – verbose
    May 25 at 8:56

is the comma to signify the boundary between the instruction interjection, 'hey', and the recipient of it ("Hey, stupid! Keep it simple")


or is it serving the function of an "and"

No. That would make no sense.

  • Comments have been moved to chat; please do not continue the discussion here.
    – NVZ
    May 23 at 17:07
  • This is how it was used in the programming department I worked in in the 1970's and was a verbal reminder of a programmer's ethos that writing complicated code when a simpler approach was available should be avoided. It was generally used in a light-hearted manner and not taken as in insult. The only political correction I ever heard was "Keep it simple Simon" to avoid the directly saying the recipient of the observation was stupid. Aurally I don't recall any of the tech people saying the phrase as if there were a comma in it.
    – traktor
    May 24 at 14:47
  • While using a comma in place of "and", acronyms are known for having odd phrasing - another situation with odd phrasing is headlines, which are often abbreviated and end up sounding similar: "New Government Policy Simple, Stupid" sounds alright to my ears.
    – IronEagle
    May 25 at 2:35

It's rare to use a comma between a pair of predicative adjectives unless one is in apposition (a synonym to elucidate [a] or a near-synonym to [1] develop, [2] amend (make a minor correction or add precision) or [3] bracket (where an 'and' is considered too divisive and a slash too informal) the required sense [b]):

  • [a] [T]he revelations have been uniformly anticlimactic. The exchanges, most reports agree, are quotidian, mundane. [Rebecca Traister; The Cut; 2015]

  • [b1] [The dog was] found to be very thin, emaciated .... RSPCA Cymru; Facebook; 2018]

  • [b2] [W]hile the reserves are large, enormous, at the present time, the battalions have been far under strength. [Hansard; Army Estimates; Vol 160; 1906-7]

  • [b3] She claimed that Lord Haw Haw's words were misleading, disingenuous.

  • [b3] The results of the experiment were disappointing, frustrating.

Since this is not the case with 'keep it simple, stupid', it is highly likely that 'stupid' here is a vocative, as in 'keep it simple, Stan'.

  • 2
    I would say that stupid could be understood as a near synonym to simple (OED: stupid, foolish, feeble-minded) that adds precision (stupid is a stupider simple). It may not seem likely, but we really don’t know. May 23 at 23:14
  • 'Keep it fairly stupid ...' seems extremely unlikely in any meaningful adjuration. May 24 at 9:28

Like many idioms, different interpretations are often just as valid as one another.

"Hey Stupid, Keep it simple!" is pretty self explanatory. "Don't be stupid, do things simply"

"Keep it simple (and) Stupid" works as an admonishment to keep your work straightforward and choose the "dumb" approach rather than being too clever about it.

Anecdotally, I work in the software industry, and there are always many many different ways to accomplish any given task.
In general, the accepted attitude in my place of work is that it's better to write a big sprawling piece of code using simple techniques than a clever and efficient solution.

Clever code is dense code, and dense code is often difficult to immediately understand for other developers. Chunky and Dumb code is comparatively easy to pick up and modify without wasting serious time analysing what your clever colleague did.
Given that time is money and there is no prize for writing beautiful code, it's almost always better to reserve your cleverness for things that really merit it.

"Keep it simple and stupid" is a mantra in my team.

  • 2
    Stupidity, in the literal sense, is a characteristic of human beings. What exactly does it mean to characterise something other than a human being as stupid (or dumb)? Moreover stupidity is normally regarded as something undesirable, so it is puzzling why keeping something stupid would be recommended. All this needs to be explained before reading the comma as and can be regarded as even a viable candidate for a reasonable interpretation of this saying.
    – jsw29
    May 22 at 20:31
  • 2
    @jsw29 "What exactly does it mean to characterise something other than a human being as stupid (or dumb)?", well I don't agree "stupid errors" are a thing (and can be done by not-stupid people too). In addition, "stupid code" is something that is not a negative thing in a software development context (see this, for example). It may be considered "programmer jargon". Programmers are encouraged to write "stupid code" because it means it will be more reliable. May 22 at 22:50
  • 4
    Everyone is stupid sometimes. KISS is acknowledging that the poor sap who has to understand your code in a year's time might be you.
    – Miral
    May 23 at 0:15
  • 3
    @Miral Even a few weeks later can be enough to have to re-analyze your own code just to be able to understand what you previously did. Even if the code was well-documented. And you usually realize at that point you over-complicated things.
    – Tonny
    May 23 at 11:26
  • 4
    @Miral A related observation is that if you write the "cleverest" code you can, you won't be clever enough to debug it.
    – user888379
    May 23 at 12:06

As a native english speaker, it clearly reads to me "keep it simple [you] stupid [person]". The tone is lighthearted although slightly brash.

To avoid the brashness, there are alternate variations (which are most certainly backronyms):

  • "keep it simple, silly"
  • "keep it stupid simple" (which means "keep it utterly simple")

But to underscore: the usage of the term "stupid" squarely describes a proverbial person.

Some suggest that the phrase has a softer meaning, but this is not at all true. Nobody would phrase a statement like "keep it simple utterly" unless rambling when speaking. And consider that the word "stupid" here is a shortened form of the word "stupidly", having its -ly suffix omitted. In every case where "stupid" is used as an adjective without its suffix (e.g. "stupid simple", "stupid easy", "stupid smart") it always precedes its object. It never comes after. So the plain interpretation (and only interpretation) is "keep it simple, [you] stupid [person]".

  • 1
    It should be noted that this answer introduces (and then rightly rejects) a third possibility, in addition to the two offered by the OP.
    – jsw29
    May 24 at 19:44

Having been a techie for the last 50 years, on and off, here is what I know. It is really easy when on the hunt for the "perfect solution" to go down a rabbit hole of modifications to the initial design, with a result that is less than robust (think Rube Goldberg).

"Keep it simple, Stupid" is a rejoinder the designers/engineers gave to THEMSELVES to keep focused on the solving the problem and not keep trying to fix the solution.

Calling yourself Stupid should not offend anyone.

  • How exactly does this address the question? The question is not about the overall meaning of the recommendation to keep things simple, which is obvious.
    – jsw29
    May 24 at 15:13
  • @jsw29 the question is about the meaning of the word "stupid". This answer is trying to address the harshness of the most obvious interpretation. I think it's misguided, because I've seen it used more often to refer to somebody else's work rather than your own when it looks like they're over-complicating things. May 25 at 3:35

I’ve always understood it as a vocative (Keep it simple, [O] stupid [person].) There are other similar sayings, like James Carville saying about the 1992 U.S. presidential election, “It’s the economy, stupid.”

I’d say the other way, “Keep it Simple and Stupid,” or “Keep it stupidly simple.” I don’t think a list without a conjunction would be grammatical here.

I’ve also frequently heard, “Keep it simple, shithead.” (No, not addressed at me.)


It is both.

The ambiguity helps bring the message across, as the message serves as an example of how using ambiguous but technically correct grammar makes it difficult to interpret a basic four word sentence.

  • 3
    Lacking a citation, I would disagree with this interpretation. It clearly reads to me as addressing someone as "stupid" telling them to "keep it simple". Not "keep it simple (and) stupid" at all. May 23 at 18:44
  • 1
    Per Edwin Ashworth's answer, this isn't actually a case where it can be correct grammar. Even if it were, ambiguity isn't conducive to understanding -- and trying to make an extremely short and simple sentence somehow unintelligible absolutely detracts from the actual point. May 23 at 21:19

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