late 14c., "imbecile, one who is in dotage or second childhood;" see dote (v.) + -ard. Sense of "one who dotes, one who is foolishly fond" (c. 1600) is now rare or obsolete. Other noun derivatives of dote, all in the sense "fool, simpleton" in Middle English were dotel (late 14c.), doterel (late 15c.), doti-poll (c. 1400; see doddypoll).

"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.