abrupt, agile, alacritous, alert, apt, breakneck, brief, brisk, cometary, cursory, dashing, decisive, dispatchful, double-quick, eagle-winged, electrifying, expeditious, express, fast, festinate, feverish, flashing, fleet, flickering, flying, furious, galloping, hair-trigger, hasty, headlong, hurried, hustling, immediate, impetuous, impulsive, instant, instantaneous, last-minute, light-footed, light of heel, lively, mercurial, meteoric, nerve-shattering, nimble-footed, nimble, on the spot, passing, precipitant, precipitate, precipitous, prompt, punctual, quick, quick as lightning, quick as thought, raking, rapid, ready, reckless, running, sharp, shocking, short-term, short-termed, short, short and sweet, slap-bang, slapdash, smart, snap, snappy, spanking, spry, startling, sudden, summary, superficial, surprising, swift, unanticipated, unexpected, unforeseen, unlooked-for, unpredicted, urgent, winged