Synonyms for fast

modified

1. Rapid

   swift, fleet, quick, speedy, brisk, flying, expeditious, express, accelerated, hasty, nimble, winged, mercurial, lightninglike, flashing, swift-footed, hypersonic, high-speed, active, electric, agile, ready, dashing, swift as an arrow, quick as lightning, like a flash, quick as thought, racing, fleeting, up-tempo, hurried, precipitate, breakneck, headlong, like a bat out of hell*, lickety-split*, like a house afire*, hellbent*, on the double*, at warp speed*.

   Antonyms slow*, sluggish, tardy.

2. Firmly fixed

   secure, attached, immovable; see firm 1.

3. Promiscuous

   wanton, loose, wild, flirtatious; see lewd 2.

4. Permanent in color

   fadeproof, colorfast, durable, lasting, washable, vat-dyed, indelible, waterproof, fade-resistant.

play fast and loose (with)*

noun

fast and rapid are generally interchangeable in expressing the idea of a relatively high rate of movement or action, but fast more often refers to the person or thing that moves or acts, and rapid to the action a fast typist, rapid transcription; swift implies great rapidity, but in addition often connotes smooth, easy movement; fleet suggests a nimbleness or lightness in that which moves swiftly; quick implies promptness of action, or occurrence in a brief amount of time, rather than velocity a quick reply; speedy intensifies the idea of quickness, but may also connote high velocity a speedy recovery, a speedy flight; hasty suggests hurried action and may connote carelessness, rashness, or impatience

verb