I. adjective
1.
Synonyms: sure 1, firm, secure, stable, staunch, strong
Related Word: fixed, held, inextricable, stuck, wedged
Contrasted words: insecure, loose, shaky, unstable
2.
Synonyms: faithful 1, ardent, constant, ||dinky-di, liege, loyal, resolute, staunch, steadfast, true
3.
moving, proceeding, or acting with great celerity
a fast horse
Synonyms: breakneck, expeditious, expeditive, fleet, harefooted, hasty, posthaste, quick, raking, rapid, snappy, speedy, swift
Related Word: active, alert, brisk, keen, lively
Idioms: quick as lightning, quick as thought, swift as an arrow
Contrasted words: lethargic, logy, poky, sluggish, tardy, torpid; languid, languorous; deliberate, gradual
Antonyms: slow
4.
persistent in adhering to something
a fast grip
Synonyms: firm, fixed, secure, set, tenacious, tight; compare stable 4, sure 1
Idioms: stuck fast
Contrasted words: insecure, loose, relaxed, unfirm, weak; free, unattached, unfixed
5.
Synonyms: wild 7, devil-may-care, gay, raffish, rakehell, rakish, sporty
6.
Synonyms: licentious 2, incontinent, lascivious, lecherous, lewd, libertine, libidinous, lustful, salacious, satyric
7.
sexually promiscuous--usually used of a woman
she's said to be fast
Synonyms: easy, light, loose, ||riggish, unchaste, wanton, whorish
Related Word: careless, heedless, lax, slack; bawdy, indecent; lascivious, lecherous, lewd, libertine, licentious, lickerish, riotous
Idioms: no better than one should be, of easy virtue
Contrasted words: chaste, decent, decorous, modest, moral, pure, virtuous
II. adverb
1.
Synonyms: hard 7, firm, firmly, fixedly, solidly, steadfastly, tight, tightly
2.
in a rapid manner
run up the hill as fast as you know how
Synonyms: apace, chop-chop, expeditiously, flat-out, fleetly, full tilt, hastily, lickety-split, posthaste, presto, promptly, pronto, quick, quickly, rapidly, soon, speedily, swift, swiftly
Idioms: by leaps and bounds, in a flash, in a twinkling, in nothing flat, in short order, like a bat out of hell, like a blue streak, like a flash, like a house afire, like a shot, like a streak, like greased lightning, like wildfire
Contrasted words: deliberately, leisurely; apathetically, lethargically, sluggishly
Antonyms: slow, slowly