[ fast, fahst ]
See synonyms for: fastfasterfastestfasting on

adjective,fast·er, fast·est.
  1. moving or able to move, operate, function, or take effect quickly; quick; swift; rapid: a fast horse;a fast pain reliever;a fast thinker.

  2. done in comparatively little time; taking a comparatively short time: a fast race;fast work.

  1. (of time)

    • indicating a time in advance of the correct time, as of a clock.

    • noting or according to daylight-saving time.

  2. adapted to, allowing, productive of, or imparting rapid movement: a hull with fast lines;one of the fastest pitchers in baseball.

  3. characterized by unrestrained conduct or lack of moral conventions, especially in sexual relations; wanton; loose: Some young people in that era were considered fast, if not downright promiscuous.

  4. characterized by hectic activity: leading a fast life.

  5. resistant: acid-fast.

  6. firmly fixed in place; not easily moved; securely attached.

  7. held or caught firmly, so as to be unable to escape or be extricated: an animal fast in a trap.

  8. firmly tied, as a knot.

  9. closed and made secure, as a door, gate, or shutter.

  10. such as to hold securely: to lay fast hold on a thing.

  11. firm in adherence; loyal; devoted: fast friends.

  12. permanent, lasting, or unchangeable: a fast color;a hard and fast rule.

  13. Informal.

    • (of money, profits, etc.) made quickly or easily and sometimes deviously: He earned some fast change helping the woman with her luggage.

    • cleverly quick and manipulative in making money: a fast operator when it comes to closing a business deal.

  14. Photography.

    • (of a lens) able to transmit a relatively large amount of light in a relatively short time.

    • (of a film) requiring a relatively short exposure time to attain a given density.

  15. Horse Racing.

    • (of a track condition) completely dry.

    • (of a track surface) very hard.

adverb,fast·er, fast·est.
  1. quickly, swiftly, or rapidly.

  2. in quick succession: Events followed fast upon one another to the crisis.

  1. tightly; firmly: to hold fast.

  2. soundly: fast asleep.

  3. in a wild or dissipated way.

  4. ahead of the correct or announced time.

  5. Archaic. close; near: fast by.

  1. a fastening for a door, window, or the like.

Idioms about fast

  1. play fast and loose. play (def. 80).

  2. pull a fast one, Informal. to play an unfair trick; practice deceit: He tried to pull a fast one on us by switching the cards.

Origin of fast

First recorded before 900; Middle English; Old English fæst “firm”; cognate with Dutch vast, Old Norse fastr “firm,” German fest; akin to fast2

synonym study For fast

1, 2. See quick.

Other words for fast

Opposites for fast

Other definitions for fast (2 of 3)

[ fast, fahst ]

verb (used without object)
  1. to abstain from all food.

  2. to eat only sparingly or of certain kinds of food, especially as a religious observance.

verb (used with object)
  1. to cause to abstain entirely from or limit food; put on a fast: to fast a patient for a day before surgery.

  1. an abstinence from food, or a limiting of one's food, especially when voluntary and as a religious observance; fasting.

  2. a day or period of fasting.

Origin of fast

First recorded before 1000; Middle English fasten, festen, Old English fæstan; cognate with German fasten, Gothic fastan, Old Norse fasta

Other words from fast

  • un·fast·ing, adjective

Other definitions for fast (3 of 3)

[ fast, fahst ]

  1. a chain or rope for mooring a vessel.

Origin of fast

First recorded in 1670–80; alteration, by association with fast1 (in the sense “firmly tied”), of late Middle English fest “fastening, mooring rope,” from Old Norse festr “mooring rope, cable,” from Old Norse fastr “fixed, firm”; cf. fasten, fast1 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use fast in a sentence

  • He was exceedingly religious, and up to the time of his marriage had led a life devoted to prayer, fasting, and warfare.

  • The prophet describes the judgments that shall fall upon the people, and invites them to fasting and prayer.

  • The people inquire concerning fasting: they are admonished to fast from sin.

  • Trance and ecstasy were the two avenues he knew to divinity; fasting and seclusion the means employed to discover them.

    The Myths of the New World | Daniel G. Brinton
  • The thing that strikes me,” began Roger, “is that he may be like those men sent to the house of God to inquire about fasting.

    Growing Up | Jennie M. Drinkwater

British Dictionary definitions for fast (1 of 2)


/ (fɑːst) /

  1. acting or moving or capable of acting or moving quickly; swift

  2. accomplished in or lasting a short time: fast work; a fast visit

  1. (prenominal) adapted to or facilitating rapid movement: the fast lane of a motorway

  2. requiring rapidity of action or movement: a fast sport

  3. (of a clock, etc) indicating a time in advance of the correct time

  4. given to an active dissipated life

  5. of or characteristic of such activity: a fast life

  6. not easily moved; firmly fixed; secure

  7. firmly fastened, secured, or shut

  8. steadfast; constant (esp in the phrase fast friends)

  9. sport (of a playing surface, running track, etc) conducive to rapid speed, as of a ball used on it or of competitors playing or racing on it

  10. that will not fade or change colour readily: a fast dye

    • proof against fading: the colour is fast to sunlight

    • (in combination): washfast

  11. photog

    • requiring a relatively short time of exposure to produce a given density: a fast film

    • permitting a short exposure time: a fast shutter

  12. cricket (of a bowler) characteristically delivering the ball rapidly

  13. informal glib or unreliable; deceptive: a fast talker

  14. archaic sound; deep: a fast sleep

  15. informal a deceptive or unscrupulous trick (esp in the phrase pull a fast one)

  16. fast worker a person who achieves results quickly, esp in seductions

  1. quickly; rapidly

  2. soundly; deeply: fast asleep

  1. firmly; tightly

  2. in quick succession

  3. in advance of the correct time: my watch is running fast

  4. in a reckless or dissipated way

  5. fast by or fast beside archaic close or hard by; very near

  6. play fast and loose informal to behave in an insincere or unreliable manner

  1. archery (said by the field captain to archers) stop shooting!

Origin of fast

Old English fæst strong, tight; related to Old High German festi firm, Old Norse fastr

British Dictionary definitions for fast (2 of 2)


/ (fɑːst) /

  1. (intr) to abstain from eating all or certain foods or meals, esp as a religious observance

    • an act or period of fasting

    • (as modifier): a fast day

Origin of fast

Old English fæstan; related to Old High German fastēn to fast, Gothic fastan

Derived forms of fast

  • faster, noun

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Idioms and Phrases with fast


In addition to the idioms beginning with fast

  • fast and furious
  • fast and loose
  • fast buck
  • fast lane
  • fast track

also see:

  • get nowhere (fast)
  • hard and fast
  • pull a fast one
  • stand one's ground (fast)
  • thick and fast

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.