Used in an ironical sense to mean legitimate, and therefore, in reality, spurious and not at all legitimate. Assumes common knowledge of the inherent Simpsons reference.

(Adj.) Used to describe a dubious or made up word, term, or phrase that is entirely plausible because it makes logical sense within existing language conventions.

Ironically, the word comulent itself is not cromulent. (See incromulent)

Origin: Television writer David X. Cohen for The Simpsons episode 3F13, "Lisa the Iconoclast".

I believe this term originated in the Animated Television Series "The Simpsons"

Expression used to legitimize another expression of dubious existence. Used in the ironic sense in that it defends the questionable use of an illigitimate or slang word with another made-up expression. The intent of the phrase is generally used in conjunction with insults to high talkers, english majors and otherwise insufferable people who feel the need to correct others. Often accompanied by a punch to the stomach.

odd or unusual

Cromulence is when a word/situation/subject seems realistic and plausible, but is actually entirely made up.