Synonyms of rapid

1 Syllable

spry, quick, fast, brisk, prompt, going, spright, flying, swift, fleet, pdq

2 Syllables

breakneck, spoondrift, dizzying, hasty, fleetest, speedier, hastier, faster, speedy, swiftest, swifter, fleeter, chute, prompter, quick-fire, hastiest, fastest, quicker, speediest, sudden, nimble, speedball, ready, fasted, screaming, express, quickest, asap, whirlwind, hurried, chop-chop, half-assed, winged

3 Syllables

mercurial, barrelling, double-quick, fleet-footed, agile, meteoric, quickened, light-footed, cyclonic, hair-trigger, subito, posthaste, alate, rapid-fire, pennate, cursory, fleetfooted, barreling, active, overnight, lively, double-time, hairtrigger, screamin'

4 Syllables

supersonic, hypersonic, instantaneous, alacritous, ultrasonic, super-sonic, easy-moving, unhindered, expeditious, nimble-footed, exertive, harefooted

5 Syllables

precipitate, expeditive, accelerated