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.
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.
krahm-U-lehn-chus-NESS (n.) A word first used on the internet via www.reddit.com, subreddit r/funny by u/FLUX-YOU, that caused mass hysteria in an attempt of discovering the definition due to the lack google results.
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)