Not simply used to refer to a frequently used word as per the use in "a perfectly cromulent word" but may be better defined as germane, or apt, synonomous with appropriate, or fitting.
This defintion suits both uses in The Simpsons' famous episode.
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.
Edna: Embiggens? I never heard that word before I moved to Springfield.
Ms.Hoover: I don't know why. It's a perfectly cromulent word.
By Bill
Cromulent
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.
You grok what I mean, yo? (person in the know) There is no such word as grok! (Buzz kill) Grok is an exceptionally cromulent word. (street wise hommes)
The third commandment of the Georgia Guidestones put in place by the Rosicrucian Order suggests that as long as the words one chooses to use cromulate well, it is irrelevant what the Oxford English Dictionary has to say on the matter.
By Mady
Cromulate
When you have passed the dating stage with someone but aren't quiet qoing out with them yet.