A “nincompoop” is a foolish or stupid person, who often flaunts his stupidity in front of others. Synonyms are: jackass, idiot, dunce, imbecile, blockhead, dummy, numbskull, birdbrain, nitwit, dimwit, dumbass, bonehead, dumbbell, silly, and moron.
Dr Johnson, in his famous Dictionary of 1755, said the word came from Latin non compos, as in the medical and legal phrase non compos mentis, meaning not mentally competent. But as the Oxford English Dictionary commented 150 years later, this supposed origin doesn’t explain versions of the word that were around in the 1600s and early 1700s, such as “nicompoop” and “nickumpoop.”
The French word nicodème means “simpleton” and may be the possible beginning of our nincompoop. A second plausible origin is the French nic à paux, a term of derision in the late 1500s. Another possibility is another phrase in French, ne comprend pas, meaning “cannot understand”. The earliest known use of the nincompoop spelling is from 1680.
John Ciardi, in A Browser’s Dictionary, asserts that it comes instead from the Dutch phrase nicht om poep, meaning “the female relative of a fool.” But, though there was once an English verb poop, meaning “to fool or cheat,” and it did come from Dutch poep, the original Dutch word meant a shit or a fart. The English slang “poop” for faeces comes from this. The association with a fool came through a slang use of the word by the Dutch in the 1600s for a migrant worker from northern Germany.
Thus, the origin of the word is a matter of speculation, although there are a few interesting theories. One of the earliest literary uses of “nincompoop” occurred in a 1676 play called The Plain Dealer, written by British playwright William Wycherley. One character scolds another, calling him a “senseless, impertinent, quibbling, drivelling, feeble, paralytic, impotent, fumbling, frigid nincompoop.”
Gosh, he could have just come right out and said, “I like you!”