Definition: uncertain, possibly "acceptable," or "fine"
“Are you a word geek like me? 8) So any way, my new favorite word is cromulent…It caught my attention because I'm a Conan fan, and I thought it was Crom-related. But the truth is cooler still.”
—Post on www.happyatheistforum.com
It is safe to say that The Simpsons has contributed a great deal to the English language. One famous example is cromulent, which was coined specifically for the 1996 episode “Lisa the Iconoclast." In reference to one character’s questioning of the use of embiggen, another says “it’s a perfectly cromulent word.” Despite being a complete fabrication, the word caught on, and seems to be made for the internet—where the most popular "favorite words" are rarely used for their intended purposes. Like the spurious cromulent, many of these words are not even entered in dictionaries, as they seem to only be trotted out as examples of one's extensive vocabulary.
Embiggen, by the way, was also said to have been created for this episode, although it had already been used in an issue of Notes and Queries from 1884, meaning "to make great." Both cromulent and embiggen have been quite successful, and stand an excellent chance of one day being used in a manner that does not slyly reference the television show that they came from.