active, acute, adroit, alacritous, alert, alive, attentive, awake, breakneck, bright, brisk, catty, dashing, deft, dexterous, dextrous, dispatchful, double-quick, eagle-winged, expeditious, express, fast, featly, fleet, flying, galloping, graceful, hair-trigger, hasty, headlong, hustling, keen, light, light of heel, light-footed, limber, lissome, lithe, lively, mercurial, neat-fingered, neat-handed, nimble, nimble-footed, on the, on the alert, on the ball, on the job, peart, precipitate, prompt, qui vive, quick, quick as lightning, quick as thought, rapid, ready, reckless, resourceful, running, sharp, sleepless, smart, snappy, spanking, speedy, sprightly, spry, supple, sure-footed, swift, tripping, unblinking, unnodding, unsleeping, unwinking, volant, wakeful, wide-awake, winged, zippy