adj. 25B6; adjective
she was as agile as a monkey : NIMBLE, lithe, supple, limber, acrobatic, fleet-footed, light-footed, light on one's feet; informal nippy, twinkle-toed; poetic/literary fleet, lightsome.
an agile mind : ALERT, sharp, acute, shrewd, astute, perceptive, quick-witted.
clumsy, stiff.