14c., "mental state," from L. affectus, pp. of afficere "act on, have influence on, to do something to," a verb of broad meaning, from ad- "to" + facere (pp. factus) "do" (see factitious). The verb meaning "to make an impression on" is attested from 1630s.
"to make a pretense of," 1660s, earlier "to assume the character of (someone)" (1590s); originally in Eng. "to aim at, aspire to, make for" (late 15c.), from M.Fr. affecter (15c.), from L. affectare "to strive after, aim at," freq. of afficere (pp. affectus) "to do something to, act on" (see