Synonyms and related words :
abrupt, agile, alacritous, bluff, bold, breakneck, brisk, ceaseless, chattering, chute, constant, continual, dashing, double-quick, eagle-winged, expeditious, express, fast, fleet, flying, galloping, hair-trigger, hasty, headlong, high-speed, hurried, hustling, immediate, impetuous, incessant, instant, instantaneous, light of heel, light-footed, lively, machine gun, mercurial, nimble, nimble-footed, oscillating, perennial, perpetual, plunging, precipitate, precipitous, prompt, pulsating, quick, quick as lightning, quick as thought, rapids, reckless, regular, repeated, riff, riffle, ripple, running, sault, sharp, sheer, shoot, snappy, spanking, speedy, staccato, steady, steep, stuttering, sudden, sustained, swift, unbroken, unceasing, unchanging, unintermitted, unintermittent, unintermitting, uninterrupted, unremitting, unstopped, unvarying, vertical, vibrating, winged