An incorrect assertion or assumption made while attempting to sound like you know what you're talking about or otherwise trying to impress an audience. Usually a slip made by someone desperate to fit in, but who is ultimately oblivious and talking out of their ass.

Such as: missing a pop culture reference or incorrectly responding to an inside joke oblivious to the fact that it was an inside joke.

Origin: A "Who Wants to be a Millionaire" question asking to finish the phrase "Snug as a..." in which "mug from doug" was a wrong answer so absurd you'd have to be completely oblivious to choose it.