'Embiggen' and 'Cromulent' were invented as 'fauxcabulary' by the authors of the Simpsons for the Episode: 'Lisa the iconoclast'.
However, unbeknownst to the scriptwriters, 'embiggen' was, it seems actually in usage as far back as 1884!
How do we know? Because it's mentioned in a letter published in volume 10 of 'Notes and Queries: A Medium of Intercommunication for Literary Men, General Readers, Etc'.
"...But fresh slang coming up destroys old slang, and it is this we must look to, and not to grammarians, to rid the dictionaries of jargon that "neweth everyday"? Are there not, however, barbarous verbs in all languages? ἀλλ' ἐμεγάλυνεν αυτοὺς ὁ λαός, but the people magnified them, to make great or embiggen, if we may invent an English parallel as ugly. After all, use is nearly everything..." C.A. Wardof Haverstock Hill(p135).
I can't tell you how much I have enjoyed researching this, th'oul interweb's great.
I am a sad character indeed. Incidentally on the first page, (p9 of the scan) of this excellent publication, there is an advertisement for a 'portmanteau'!
(The suitcase, that is, not the word that's made up of blending two words; like' brunch' for example)
Aint life wonderful?
Here if you don't believe me.