abrupt, accident-prone, agile, bluff, bold, breathless, careless, dangerous, daredevil, dashing, desperate, devil-may-care, double-quick, eagle-winged, excessive, expeditious, express, fast, fleet, flying, furious, galloping, hair-trigger, harum-scarum, hasty, headlong, hell for leather, hotheaded, hurried, hustling, impetuous, impulsive, light-footed, light of heel, lively, mad, mercurial, nimble-footed, nimble, overeager, overenthusiastic, overzealous, panting, plunging, precipitant, precipitate, precipitous, prompt, quick, quick as lightning, quick as thought, rapid, rash, reckless, running, sharp, sheer, slap-bang, slapdash, snappy, spanking, speedy, steep, sudden, swift, vertical, wanton, wild, winged