"to cheat, trick, swindle," 1703, originally a slang or cant word, of unknown origin. Perhaps Scottish from bombaze, bumbaze "confound, perplex," or related to bombast, or related to French embabouiner "to make a fool (literally 'baboon') of." Wedgwood suggests Italian bambolo, bamboccio, bambocciolo "a young babe," extended by metonymy to mean "an old dotard or babish gull." Related: Bamboozled; bamboozler; bamboozling. As a noun from 1703.
"attack with good-humored jokes and jests," 1670s, origin uncertain; said by Swift to be a word from London street slang. Related: Bantered; bantering. The noun, "good-humored ridicule," is from 1680s.
The third refinement observable in the letter I send you, consists in the choice of certain words invented by some pretty fellows; such as banter, bamboozle, country put, and kidney, as it is there applied; some of which are now struggling for the vogue, and others are in possession of it. I have done my utmost for some years past to stop the progress of mobb and banter, but have been plainly borne down by numbers, and betrayed by those who promised to assist me. [Swift, "The Tatler," No. 230, 1710]
"to deprive (a word or phrase) of its meaning," 1900, from weasel (n.); so used because the weasel sucks out the contents of eggs, leaving the shell intact. Both this and weasel-word are first attested in "The Stained-Glass Political Platform," a short story by Stewart Chaplin, first printed in Century Magazine, June 1900:
"Why, weasel words are words that suck all the life out of the words next to them, just as a weasel sucks an egg and leaves the shell. If you heft the egg afterward it's as light as a feather, and not very filling when you're hungry; but a basketful of them would make quite a show, and would bamboozle the unwary."
They were picked up at once in American political slang. The sense of "extricate oneself (from a difficult place) like a weasel" is first recorded 1925; that of "to evade and equivocate" is from 1956. Related: Weasled; weasling.