fast

¹ American  

[fast, fahst] / fæst, fɑst /

adjective

faster, fastest

1. moving or able to move, operate, function, or take effect quickly; quick; swift; rapid: a fast pain reliever;

   a fast horse;

   a fast pain reliever;

   a fast thinker.

   Synonyms:

   speedy, speedy, fleet

   Antonyms:

   slow, slow

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

   a fast race;

   fast work.

   Synonyms:

   speedy, speedy, fleet

   Antonyms:

   slow, slow

3. (of time)

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

   2. noting or according to daylight-saving time.

4. adapted to, allowing, productive of, or imparting rapid movement: one of the fastest pitchers in baseball.

   a hull with fast lines;

   one of the fastest pitchers in baseball.

5. 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.

   Synonyms:

   prodigal, wild, immoral, profligate, dissolute, dissipated

   Antonyms:

   restrained

6. characterized by hectic activity.

   leading a fast life.

   Antonyms:

   restrained

7. resistant.

   acid-fast.

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

   Synonyms:

   firm, immovable, tight, secure

   Antonyms:

   loose

9. held or caught firmly, so as to be unable to escape or be extricated.

   an animal fast in a trap.

   Synonyms:

   inextricable

10. firmly tied, as a knot.

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

12. such as to hold securely.

    to lay fast hold on a thing.

13. firm in adherence; loyal; devoted.

    fast friends.

    Synonyms:

    steadfast, faithful

14. permanent, lasting, or unchangeable: a hard and fast rule.

    a fast color;

    a hard and fast rule.

    Synonyms:

    enduring

15. Informal.

    1. (of money, profits, etc.) made quickly or easily and sometimes deviously.

       He earned some fast change helping the woman with her luggage.

    2. cleverly quick and manipulative in making money.

       a fast operator when it comes to closing a business deal.

16. Photography.

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

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

17. Horse Racing.

    1. (of a track condition) completely dry.

    2. (of a track surface) very hard.

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adverb

faster, fastest

1. quickly, swiftly, or rapidly.

2. in quick succession.

   Events followed fast upon one another to the crisis.

3. tightly; firmly.

   to hold fast.

   Synonyms:

   tenaciously, fixedly, securely

4. soundly.

   fast asleep.

5. in a wild or dissipated way.

   Synonyms:

   prodigally, wildly, recklessly

6. ahead of the correct or announced time.

7. Archaic. close; near.

   fast by.

noun

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

idioms

1. pull a fast one, to play an unfair trick; practice deceit.

   He tried to pull a fast one on us by switching the cards.

2. play fast and loose. play.

fast ² American  

[fast, fahst] / fæst, fɑst /

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.

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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.

noun

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.

fast ³ American  

[fast, fahst] / fæst, fɑst /

noun

1. a chain or rope for mooring a vessel.

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fast ¹ British  

/ fɑːst /

adjective

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

3. (prenominal) adapted to or facilitating rapid movement

   the fast lane of a motorway

4. requiring rapidity of action or movement

   a fast sport

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

6. given to an active dissipated life

7. of or characteristic of such activity

   a fast life

8. not easily moved; firmly fixed; secure

9. firmly fastened, secured, or shut

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

11. 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

12. that will not fade or change colour readily

    a fast dye

13. 1. proof against fading

       the colour is fast to sunlight

    2. ( in combination )

       washfast

14. photog

    1. requiring a relatively short time of exposure to produce a given density

       a fast film

    2. permitting a short exposure time

       a fast shutter

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

16. informal glib or unreliable; deceptive

    a fast talker

17. archaic sound; deep

    a fast sleep

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

19. a person who achieves results quickly, esp in seductions

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adverb

1. quickly; rapidly

2. soundly; deeply

   fast asleep

3. firmly; tightly

4. in quick succession

5. in advance of the correct time

   my watch is running fast

6. in a reckless or dissipated way

7. archaic close or hard by; very near

8. informal to behave in an insincere or unreliable manner

interjection

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

fast ² British  

/ fɑːst /

verb

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

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noun

1. 1. an act or period of fasting

   2. ( as modifier )

      a fast day

fast More Idioms  

More idioms and phrases containing fast

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

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Related Words

See quick.

Other Word Forms

• faster noun
• unfasting adjective

Etymology

Origin of fast¹

First recorded before 900; Middle English; Old English fæst “firm”; cognate with Dutch vast, Old Norse fastr “firm,” German fest; akin to fast ²

Origin of fast²

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

Origin of fast³

First recorded in 1670–80; alteration, by association with fast ¹ ( def. ) (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”; fasten, fast ¹

Example Sentences

She said these species spread fast in the garden, and quickly out-compete native species in the wild, overtaking important habitats like the Bluebell Woods and coastal turf.

From BBC • Apr. 3, 2026

"I started to see many articles about lead in clothing from fast fashion," says Deavers.

From Science Daily • Apr. 2, 2026

However, things are moving fast these days, so there could be surprises in either direction.

From MarketWatch • Apr. 2, 2026

The triple lock creates a big but unpredictable ratchet for the government’s social-spending bill: No one can guess over time how fast old-age social spending will grow.

From The Wall Street Journal • Apr. 2, 2026

He looked fast asleep, or dead—I was not sure which.

From "An Elephant in the Garden" by Michael Morpurgo

Related Words

• agile
• brisk
• hot
• nimble
• quick
• rapid
• swift