I write code for a living and I'm trying to find the right word for a flaw in logic. "Error" seems too vague, I'm looking specifically for a word that describes a flaw in logic.

Addendum 1: This would be an unintended flaw in logic. Addendum 2: Preferably 1 word, please.

  • 1
    If Mr. Hen's answer isn't what you are looking for, then you might want to consider giving an example or two. Some examples of logical fallacies would be:Affirming the consequent: the antecedent in an indicative conditional is claimed to be true because the consequent is true; if A, then B; B, therefore A. Denying the antecedent: the consequent in an indicative conditional is claimed to be false because the antecedent is false; if A, then B; not A, therefore not B.
    – Kevin
    Apr 12, 2011 at 18:40
  • @Kevin Think, man, think! The OP can't go into a functional spec review and talk about "logical fallacies!" He'd be hooted from the room :-) Apr 12, 2011 at 18:54
  • @Pete, I completely glossed over the "I write code" part.
    – Kevin
    Apr 12, 2011 at 19:26
  • What's an intended flaw...in anything?
    – Mitch
    Apr 12, 2011 at 19:38
  • 1
    @Mitch: Sabotage.
    – MrHen
    Apr 13, 2011 at 0:10

4 Answers 4


Depends on the point of view, doesn't it?

When someone finds a logic error in my code, I call it "a small misunderstanding" and blame it on marketing's requirements doc.

When I find a logic error in somebody else's code, I call it "a total fsck()ing disaster!" and blame it on management's hiring policies.

In general, though, "bug" is not only the right word; it's the only word. You can't go wrong with "bug" in any context having to do with code.


A "logical fallacy" means:

Clearly defined error in reasoning used to support or refute an argument, excluding simple unintended mistakes.

Wikipedia provides a good list of fallacies. You may be able to find a more descriptive term for whatever error you happened across.

Response to addendum: "Fallacy" works fine on its own. Fallacies imply nothing about intention and context will clue people into the implicit "logic" topic. If that doesn't do it for you, here are a few other options:

  • irrational
  • illogic
  • mistake
  • accident

If you are looking for a term to use in class or variable names, "flaw" or "error" would probably be fine with some good supporting documentation describing the problem. logicError is certainly legible.

  • Sure, I added an addendum
    – sooprise
    Apr 12, 2011 at 18:39

It may seem too easy but

logical flaw


logical error

works, to distinguish it from other flaws or errors (like typos or errors of fact).

  • I was hoping for a one word answer, but maybe the English language doesn't include what I'm looking for.
    – sooprise
    Apr 12, 2011 at 18:39
  • 1
    There are single words for different kinds of errors: typo (for transcription error), lacuna (missing info), solecism (a grammatical error), untrue (a factual error), fallacy (an error in argumentation, of which a particular kind is a logical fallacy (back to where we started))...but I can't find a single word for 'logical error'. As succinct as single words are, a two word version can say what it means just as easily.
    – Mitch
    Apr 12, 2011 at 19:37

How about "illogicality"? I just made it up, but then I googled it, and it already existed!

I can't find a specific definition for it, but it's listed as a noun under "illogical" in several dictionaries....So, most basic definition would be "a thing that is illogical."

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