I am looking for one word to describe making a mistake that ordinarily should have been well within your ability to perform properly.

For example, if someone is considered especially gifted in perceptual organization, yet they fail to notice how to open an extremely simple lock, what type of mistake is that?

The connotation I'm looking for is something like a gross blunder, or an uncharacteristically stupid mistake.

The one word can be any type of word, i.e. noun, adjective, verb, etc. For example:

  • "You have made a (noun)."
  • "You just (verb)ed."
  • "That was very (adjective)."

Words like "gaffe", "blunder", "mistake", to me at least, don't indicate the extreme uncharacteristicness of the stupidity involved.

  • 1
    What's wrong with blunder?
    – NVZ
    Sep 10, 2016 at 19:25
  • I just put a sentence at the end of my question, saying "blunder" etc don't seem to indicate the extreme uncharacteristicness of the mistake. Sep 10, 2016 at 19:26
  • 1
    "You made a serious mistake" - Batman youtube.com/watch?v=b-7VqmAF7r0
    – NVZ
    Sep 10, 2016 at 19:56
  • 2
    Very informal but, brain fart?
    – 54 69 6D
    Sep 10, 2016 at 20:03
  • @54696D Yes, I was thinking something like that, but something more formal. Sep 10, 2016 at 20:05

7 Answers 7


How about lapse (sometimes referred to as mental lapse)?

From Oxford Dictionaries:

lapse: a temporary failure of concentration, memory, or judgment

As per the OP's question, a lapse is one word that describes "making a mistake [on a task] that ordinarily should have been well within [one's] ability to perform properly ... an uncharacteristically stupid mistake"

Brain fart would be a good two-word answer.

From Oxford Dictionaries:

brain fart: a temporary mental lapse or failure to reason correctly


It's two words, but consider using:

Senior moment - an instance of momentary forgetfulness or confusion that is attributed to the aging process

Although senior is part it, this can apply to anyone who fails to do something they usually could.

  • 3
    This only applies to old people. I don't agree with the last sentence at all.
    – TonyK
    Sep 10, 2016 at 22:24

The word braino might fit the bill. It is modelled on the wort typo: it means a random error in the cognitive process.

"You just put salt in your coffee!"
"Oh damn. Braino."



In baseball statistics, an error is an act, in the judgment of the official scorer, of a fielder misplaying a ball in a manner that allows a batter or baserunner to advance one or more bases or allows an at bat to continue after the batter should have been put out. –Wiki

"... should have been well within your ability to perform properly."

I like to use the (incorrect) phrase, [I/you] have errored.

You gave each kid five bucks and let them loose in the candy store? You, sir, have errored.


How about flub? It can be used as both a noun and a verb (I flubbed; what a flub) and has the meaning you're asking for. It means to perform poorly; blunder; bungle. It seems to have a connotation of extreme and uncharacteristic stupidity, as if you were getting your nose rubbed in the dirt.


I know this is technically a single-word request, but I would use "egregious blunder". Gross blunder, which you used in your own post, isn't too bad either.


Here's a list of synonyms: http://www.thesaurus.com/browse/screw-up

Here's what I like the best:

  • "You made a gaffe or a major boo-boo (embarrassing mistake)."
  • "You just had a major [engine] misfire."
  • "That was very sloppy."

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