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.