rapid synonym | Thesaurus.com

Main Entry:	rapid
Part of Speech:	adjective
Definition:	very quick
Synonyms:	accelerated, active, agile, breakneck, brisk, double time, expeditious, express, fast, fleet, flying, hasty, hurried, lively, mercurial, nimble, on the double*, precipitate, prompt, ready, speedy, spry, swift, winged, expeditive, fleet of foot, in nothing flat, light-footed, like a house on fire, quick as a wink, quickened, really rolling, screaming
Notes:	a turbulent, rock-obstructed river area is rapid(s) and steep rapids make a cataract
Antonyms:	languishing, leisurely, slack, slow

* = informal/non-formal usage

Main Entry:	agile
Part of Speech:	adjective
Definition:	physically or mentally nimble, deft
Synonyms:	active, acute, alert, athletic, brisk, buoyant, clever, dexterous, energetic, fleet, frisky, limber, lithe, lively, mercurial, prompt, quick, quick-witted, rapid, ready, sharp, spirited, sportive, sprightly, spry, stirring, supple, swift, vigorous, vivacious, winged, zippy, bustling, easy-moving, quick on the draw, quick on the trigger, spright, twinkle toes
Antonyms:	brittle, clumsy, stiff

Main Entry:	breakneck
Part of Speech:	adjective
Definition:	extremely fast
Synonyms:	excessive, flat out, headlong, lightning, precipitate, rapid, reckless, speedy, whirlwind, at full tilt, dangerously fast, high-speed
Antonyms:	extremely slow

Main Entry:	chute
Part of Speech:	noun
Definition:	ramp, slope
Synonyms:	channel, course, fall, gutter, incline, rapid, runway, slide, trough

Main Entry:	cursory
Part of Speech:	adjective
Definition:	casual, hasty
Synonyms:	brief, careless, desultory, fast, half-baked, haphazard, hit or miss, hurried, offhand, passing, perfunctory, quick, random, rapid, shallow, short, sketchy, slapdash, slight, sloppy, speedy, summary, superficial, swift, uncritical, depthless, half-assed
Antonyms:	complete, meticulous, painstaking, perfect, thorough, unhurried

* = informal/non-formal usage

Main Entry:	expeditious
Part of Speech:	adjective
Definition:	immediate, speedy
Synonyms:	active, alert, breakneck, brisk, diligent, effective, effectual, efficient, fast, fleet, hasty, instant, nimble, prompt, punctual, quick, rapid, ready, swift
Antonyms:	retarded, slow, pokey

Main Entry:	fleet
Part of Speech:	adjective
Definition:	quick in movement
Synonyms:	agile, breakneck, brisk, expeditious, fast, flying, hasty, lively, mercurial, meteoric, nimble, on the double, rapid, speedy, swift, winged, barreling, expeditive, in nothing flat, like greased lightning, nimble-footed, screaming, speedball
Antonyms:	clumsy, slow

* = informal/non-formal usage

Main Entry:	hasty
Part of Speech:	adjective
Definition:	speedy; without much thought
Synonyms:	abrupt, agile, brash, breakneck, brief, brisk, careless, cursory, eager, expeditious, fast, fiery, fleet, fleeting, foolhardy, headlong, heedless, hurried, ill-advised, impatient, impetuous, impulsive, incautious, inconsiderate, madcap, on the double, passing, perfunctory, precipitate, prompt, pronto, quick, quickie, rapid, rash, reckless, rushed, short, slapdash, snappy, sudden, superficial, swift, thoughtless, urgent, PDQ, chop-chop*, harefooted, quickened, slambang
Antonyms:	delayed, lazy, slow, lingering, loitering

* = informal/non-formal usage

Main Entry:	instantaneous
Part of Speech:	adjective
Definition:	immediate
Synonyms:	direct, fast, in a flash, instant, momentary, quick, rapid, spontaneous, transitory, hair-trigger
Antonyms:	delayed, eventual, late, later

Main Entry:	meteoric
Part of Speech:	adjective
Definition:	brief, sudden
Synonyms:	dazzling, ephemeral, fleeting, momentary, rapid, spectacular, speedy, swift, transient, flashing, overnight
Antonyms:	slow

Main Entry:	posthaste
Part of Speech:	adjective, adverb
Definition:	fast
Synonyms:	breakneck, directly, expeditious, flat-out, fleet, hastily, hasty, headlong, lickety-split, pell-mell, promptly, pronto, quick, quickly, rapid, rapidly, speedily, speedy, swift, swiftly, at once, double-quick, fleetly, full tilt, straightaway
Antonyms:	eventually, slow, slowly

* = informal/non-formal usage

Main Entry:	prompt
Part of Speech:	adjective
Definition:	early, responsive
Synonyms:	alert, apt, brisk, eager, efficient, expeditious, immediate, instant, instantaneous, on the ball, on the nose, on time, precise, punctual, quick, rapid, ready, smart, speedy, swift, timely, vigilant, watchful, wide-awake, willing, on the button, on the dot, unhesitating
Antonyms:	late, negligent, slow, tardy

* = informal/non-formal usage

Main Entry:	speedy
Part of Speech:	adjective
Definition:	fast, quick
Synonyms:	accelerated, agile, breakneck, brisk, expeditious, express, fleet, hasty, headlong, hurried, immediate, lissome, lively, nimble, precipitate, prompt, rapid, ready, snappy, summary, swift, winged, alacritous, harefooted, quick-fire, rapid-fire, supersonic, ultrasonic
Antonyms:	delayed, tardy, halted, slowed

Main Entry:	sudden
Part of Speech:	adjective
Definition:	unexpected; happening quickly
Synonyms:	abrupt, accelerated, acute, expeditious, fast, flash, fleet, hasty, headlong, hurried, immediate, impetuous, impromptu, impulsive, out of the blue*, precipitate, precipitous, quick, rapid, rash, rushing, spasmodic, swift, unforeseen, unusual, precipitant, quickened, speeded, subito
Antonyms:	expected, slow

* = informal/non-formal usage

Main Entry:	swift
Part of Speech:	adjective
Definition:	very fast
Synonyms:	abrupt, breakneck, expeditious, express, fleet, flying, hasty, headlong, hurried, nimble, on the double, precipitate, prompt, pronto, quick, rapid, ready, short, short-lived, snappy, spanking*, speedy, sudden, unexpected, winged, alacritous, barrelling, cracking, double-quick, fleet-footed, in nothing flat, like crazy, like mad, screaming, shaking a leg, speedball, supersonic
Antonyms:	delayed, slow, sluggish

* = informal/non-formal usage

Main Entry:	whirlwind
Part of Speech:	adjective
Definition:	very fast
Synonyms:	hasty, headlong, hurricane, impetuous, impulsive, lightning, quick, rapid, rash, short, speedy, swift, tornado, cyclonic
Antonyms:	slow

Main Entry:	white water
Part of Speech:	noun
Definition:	fast-flowing water
Synonyms:	lather, rapid, rapids, spray, suds, surf, breakers, soapsuds, spindrift, spoondrift, wild water

Main Entry:	active
Part of Speech:	adjective
Definition:	having movement
Synonyms:	alive, astir, effective, efficacious, flowing, hasty, mobile, movable, moving, operating, operative, progressive, pushing, rapid, restless, rolling, running, rushing, rustling, simmering, speedy, traveling, walking, working, at work, bustling, exertive, functioning, going, impelling, in force, in play, in process, shifting, speeding, streaming, swarming, turning
Antonyms:	dormant, immobile, inactive, inert, lazy, sluggish, abeyant

Main Entry:	fast
Part of Speech:	adjective
Definition:	speedy
Synonyms:	PDQ, accelerated, active, agile, blue streak, breakneck, brisk, chop-chop, dashing, double-time, electric, expeditious, expeditive, flashing, fleet, fleeting, flying, hairtrigger, hasty, hot, hurried, hypersonic, in a jiffy, in nothing flat, lickety split, like a bat out of hell, like all get out, like crazy, like mad, nimble, on the double, posthaste, presto, pronto, quick, racing, rapid, ready, screamin', snap, snappy*, speedball, supersonic, swift, velocious, winged
Antonyms:	plodding, slow, tardy, unhurried

* = informal/non-formal usage

Main Entry:	quick
Part of Speech:	adjective
Definition:	fast, speedy
Synonyms:	abrupt, accelerated, active, agile, alert, animated, breakneck, brief, brisk, cursory, curt, double time, energetic, expeditious, express, fleet, flying, hasty, headlong, hurried, immediate, impatient, impetuous, instantaneous, keen, lively, mercurial, nimble, on the double, perfunctory, posthaste, prompt, pronto, rapid, snappy, spirited, sprightly, spry, sudden, swift, winged*, ASAP, a move on, expeditive, going, harefooted, move it, the lead out
Antonyms:	lazy, slow, sluggish