discomfit (v.) Look up discomfit at Dictionary.com
c.1200, as an adjective, from Old French desconfit "vanquished, defeated," past participle of desconfire "to defeat, destroy," from des- "not" (see dis-) + confire "make, prepare, accomplish," from Latin conficere (see confection).

Used as a verb in English from c.1300. Weaker sense of "disconcert" is first recorded 1520s in English, probably by confusion with discomfort. Related: Discomfited; discomfiting.