act, v. [behave], deport one's [self]; [play], [personate], [impersonate], [mimic]; [feign], [counterfeit], [simulate], dissemble.
acting, n. [personation], [impersonation], [simulation], [feigning], stage-playing, histrionicism, histrionism, affectation [mimicry], pantomime (acting without speaking).
action, n. [agency], operation, [movement], [activity]; pl. [conduct], [behavior], [deportment], deeds; (Law) [lawsuit], [litigation], [suit]. Antonyms: [inaction], stagnation, [inactivity], inertia.
active, a. [brisk], [nimble], [agile], [sprightly], [spirited]; [strenuous], [diligent], [enterprising]; operative, [efficacious], drastic; [effective]; transitive. Antonyms: [inactive], [passive], [latent], quiescent, sedentary.
activity, n. operation, [action]; [liveliness], briskness, [agility], [sprightliness], [strenuousness]. Antonyms: [inactivity], passiveness, quiescence.
actor, n. doer, participant, [performer]; comedian; tragedian; thespian; [impersonator], personator, mime, [mimic]; pantomimist; barnstormer; hamfatter; supernumerary.
actress, n. tragedienne; comedienne; ingenue, soubrette, understudy; [star].
actual, a. [real], veritable. Antonyms: potential, nominal, hypothetical.
actuality, n. [reality], veritableness.
actuate, v. instigate, impel, [incite].