How Well Do You Know English Slang?
1610s (n.), from French fainéant (16c.) "do-nothing," from fait, third person singular present tense of faire (see factitious) + néant "nothing" (cf. dolce far niente).
A French folk etymology of Old French faignant (14c.), present participle of faindre "to feign" (see feign). As an adjective, from 1855.