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, fleet

   Antonyms:

   slow

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

   a fast race;

   fast work.

   Synonyms:

   speedy, fleet

   Antonyms:

   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)

fasts, present (3rd person singular) fasted, past participle, past fasting present participle

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)

fasts, present (3rd person singular) fasted, past participle, past fasting present participle

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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Synonym Usage

See quick.

Other Word Forms

Derived Forms

• unfasting
  adjective
• faster
  noun

Conjugated Forms

Present

• has fasted
  perfect 3rd person singular
• have fasted
  perfect
• have been fasting
  perfect progressive
• is fasting
  progressive 3rd person singular
• fasts
  singular 3rd person
• am fasting
  progressive 1st person singular
• are fasting
  progressive
• fasting
  participle
• has been fasting
  perfect progressive 3rd person singular

Past

• had fasted
  perfect
• were fasting
  progressive plural
• fasted
  simple
• fasted
  participle
• was fasting
  progressive singular
• had been fasting
  perfect progressive

Future

• will fast
  simple
• will have fasted
  perfect
• will be fasting
  progressive
• will have been fasting
  perfect progressive

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”; cf. fasten, fast ¹

Explanation

When you see fast, you might think of Olympic runner Usain "Lightning" Bolt or a Porsche 911 Turbo. Alternatively, and quite confusingly, fast also means to refrain from eating for a certain period, usually for religious reasons. Fast is another of those deceptively simple words that have a number of other meanings beyond their most common usages. If something "sticks fast" it means it cannot be removed — like a leech or a stain. "To stand fast" means not to give up your point of view or to remain loyal. Then there's also the slang meaning of living beyond the constraints of normal behavior — as in "the fast life," "the fast track," or "the fast lane."

Example Sentences

Fast facts: Tom Holland reprises his role as Marvel’s Spidey, aka Peter Parker, in this long-awaited follow-up to 2021’s “Spider-Man: No Way Home.”

From The Wall Street Journal • Jun. 6, 2026

Fast forward to 2008 and the Champions League semi-final.

From BBC • Jun. 5, 2026

Fast forward to Monday, when Son strode out of a black Mercedes at the Élysée Palace to be fêted by Emmanuel Macron—the fourth world leader to publicly host him in the past two years.

From The Wall Street Journal • Jun. 4, 2026

Fast selling is a bit of good news for the troubled truck.

From Barron's • Jun. 3, 2026

Fast food wrappers are littered next to his duffle bag.

From "South of Somewhere" by Kalena Miller

Related Words

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