Moving quickly and lightly:
— Sleek and agile as a gymnast.

synonyms: nimble, quick, spry.

Roget 274: fast, speedy, swift, rapid, quick, fleet; aliped^†; nimble, agile, expeditious; express; active etc. 682; flying, galloping etc. v.; light footed, nimble footed; winged, eagle winged, mercurial, electric, telegraphic; light-legged, light of heel; swift as an arrow etc. n.; quick as lightning etc. n., quick as a thought.    ... show more

Roget 682: active, brisk, brisk as a lark, brisk as a bee; lively, animated, vivacious; alive, alive and kicking; frisky, spirited, stirring.    nimble, nimble as a squirrel; agile; light-footed, nimble-footed; featly^†, tripping.    quick, prompt, yare^†, instant, ready, alert, spry, sharp, smart; fast etc. (swift) 274; quick as a lamplighter, expeditious; awake, broad awake; go-ahead, live wide-awake [U.S.] etc. (intelligent) 498.    forward, eager, strenuous, zealous, enterprising, in earnest; resolute etc. 604.    industrious, assiduous, diligent, sedulous, notable, painstaking; intent etc. (attention) 457; indefatigable etc. (persevering) 604.1; unwearied; unsleeping^†, never tired; plodding, hard-working etc. 686; businesslike, workaday.    bustling; restless, restless as a hyena; fussy, fidgety, pottering; busy, busy as hen with one chicken.    working, at work, on duty, in harness; up in arms; on one's legs, at call; up and doing, up and stirring.    busy, occupied; hard at work, hard at it; up to one's ears in, full of business, busy as a bee, busy as a one-armed paperhanger.    meddling etc. v.; meddlesome, pushing, officious, overofficious^†, intrigant^†.    astir, stirring; agoing^†, afoot; on foot; in full swing; eventful; on the alert, etc. (vigilant) 459.    ... show more

Polish: zwinny

Mentally quick:
— An agile mind.

synonym: nimble.

Polish: giętki