1640s, with -ous, from ambidexter (adj.) "double-dealing" (1610s), from French ambidextre or directly from Latin ambidexter, literally "right-handed on both sides," from ambi- "both" (see ambi-) + dexter "right-handed" (see dexterity). Its opposite, ambilevous "left-handed on both sides, clumsy" (1640s) is rare. Ambidexter as a noun, "one who takes bribes from both sides," is attested from 1530s and is the earliest form of the word in English; its sense of "one who uses both hands equally well" appears by 1590s.