How popular is the word “cromulent”? If I use this word in conversation with native speakers, doesn’t it look out of place?

In today’s post, “What’s the antonym for recommend?” an answerer answered "I discourage the blue sweater sounds perfectly cromulent.”

As I am utterly unfamiliar with the word, “cromulent,” I looked for its meaning in Oxford, Cambridge and Merriam-Webster online dictionaries to find none of them registers this word. And Window Word 7 spelling checker keeps suggesting me to correct “cromulent” into “corpulent” or “crapulent” at this right moment I’m writing this question.

However, Wikitionary registers “cromulent,” and provides the definition as:

• Fine, acceptable or normal; excellent, realistic, legitimate or authentic.

(Origin) 1996 February 18, Matt Groening et al., “Lisa the Iconoclast”, The Simpsons, Season 7, Episode 16.

I wonder how popular this word is among English speaking world. If a non-native speaker like me whose stock of vocabulary is very limited and are totally unsure of the good command of English uses this word in conversation with you - native speakers, does it sound out of place or overreaching?

• 'Cromulent' is simply a made-up word, in fact, made up to describe another made-up word from the Simpson's animated show.
• It was coined, as you noted, by the writers for that Simpsons episode in 1996. It has only caught on in certain circles. A very small minority of English speakers would recognize it and use it properly (as a synonym of 'acceptable').
• Merriam-Webster, OED, etc, regularly try to add new words that are accepted with their given standards. I'm not sure exactly what standards each dictionary has, but usually frequency of use or usage in major/commonly read publications is one measure. A staff with editorial oversight usually makes these decisions to publish new words as officially recognized.
• Wikipedia and Wiktionary are publically editable. There is some editorial oversight but only to the extent of stopping bad behavior, not really of content. As democratic and well-meaning as that is, it may not be particularly accurate or have the right nuance as to frequency of usage (not that M-W or OED is necessarily better at that, but their editorial process is more painstaking).

I would steer clear of that one. It only exists as a joke in that Simpsons episode you referenced. Ms. Hoover only used it to support another joke word: embiggens. No one uses it seriously, but you might get a laugh out of it.