fast
1 Americanadjective
-
faster,
comparative
-
fastest
superlative
-
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.
- Antonyms:
- slow
-
done in comparatively little time; taking a comparatively short time: fast work.
a fast race;
fast work.
- Antonyms:
- slow
-
(of time)
-
indicating a time in advance of the correct time, as of a clock.
-
noting or according to daylight-saving time.
-
-
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.
-
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
-
characterized by hectic activity.
leading a fast life.
- Antonyms:
- restrained
-
resistant.
acid-fast.
-
firmly fixed in place; not easily moved; securely attached.
- Antonyms:
- loose
-
held or caught firmly, so as to be unable to escape or be extricated.
an animal fast in a trap.
- Synonyms:
- inextricable
-
firmly tied, as a knot.
-
closed and made secure, as a door, gate, or shutter.
-
such as to hold securely.
to lay fast hold on a thing.
-
firm in adherence; loyal; devoted.
fast friends.
-
permanent, lasting, or unchangeable: a hard and fast rule.
a fast color;
a hard and fast rule.
- Synonyms:
- enduring
-
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.
-
-
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.
-
-
Horse Racing.
-
(of a track condition) completely dry.
-
(of a track surface) very hard.
-
adverb
-
quickly, swiftly, or rapidly.
-
in quick succession.
Events followed fast upon one another to the crisis.
-
to hold fast.
- Synonyms:
- tenaciously, fixedly, securely
-
fast asleep.
-
in a wild or dissipated way.
- Synonyms:
- prodigally, wildly, recklessly
-
ahead of the correct or announced time.
-
Archaic. close; near.
fast by.
noun
idioms
-
pull a fast one, to play an unfair trick; practice deceit.
He tried to pull a fast one on us by switching the cards.
-
play fast and loose. play.
verb (used without object)
-
fasts,
present (3rd person singular)
-
fasted,
past participle, past
-
fasting
present participle
-
to abstain from all food.
-
to eat only sparingly or of certain kinds of food, especially as a religious observance.
verb (used with object)
-
fasts,
present (3rd person singular)
-
fasted,
past participle, past
-
fasting
present participle
noun
-
an abstinence from food, or a limiting of one's food, especially when voluntary and as a religious observance; fasting.
-
a day or period of fasting.
noun
adjective
-
acting or moving or capable of acting or moving quickly; swift
-
accomplished in or lasting a short time
fast work
a fast visit
-
(prenominal) adapted to or facilitating rapid movement
the fast lane of a motorway
-
requiring rapidity of action or movement
a fast sport
-
(of a clock, etc) indicating a time in advance of the correct time
-
given to an active dissipated life
-
of or characteristic of such activity
a fast life
-
not easily moved; firmly fixed; secure
-
firmly fastened, secured, or shut
-
steadfast; constant (esp in the phrase fast friends )
-
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
-
that will not fade or change colour readily
a fast dye
-
-
proof against fading
the colour is fast to sunlight
-
( in combination )
washfast
-
-
photog
-
requiring a relatively short time of exposure to produce a given density
a fast film
-
permitting a short exposure time
a fast shutter
-
-
cricket (of a bowler) characteristically delivering the ball rapidly
-
informal glib or unreliable; deceptive
a fast talker
-
archaic sound; deep
a fast sleep
-
informal a deceptive or unscrupulous trick (esp in the phrase pull a fast one )
-
a person who achieves results quickly, esp in seductions
adverb
-
quickly; rapidly
-
soundly; deeply
fast asleep
-
firmly; tightly
-
in quick succession
-
in advance of the correct time
my watch is running fast
-
in a reckless or dissipated way
-
archaic close or hard by; very near
-
informal to behave in an insincere or unreliable manner
interjection
verb
noun
Synonym Usage
See quick.
Other Word Forms
Derived Forms
Inflected Forms
Adjectives
Participles
Conjugated Forms
Present
-
fastsimple
-
fastssimple
-
have fastedperfect
-
has fastedperfect
-
am fastingprogressive
-
are fastingprogressive
-
is fastingprogressive
-
have been fastingperfect progressive
-
has been fastingperfect progressive
Past
-
fastedsimple
-
had fastedperfect
-
was fastingprogressive
-
were fastingprogressive
-
had been fastingperfect progressive
Future
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."
Vocabulary lists containing fast
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
A series of follow-up experiments with paid participants showed that people in general associate quick responses with overall competence—and that even those who say they don’t expect fast replies still favor those who give them.
From The Wall Street Journal ● Aug. 18, 2026
He says although the platform's "done a lot of things right" he believes it got "too big too fast".
From BBC ● Aug. 18, 2026
“I was so fast, big guys that age couldn’t keep in front of me,” he said.
From Los Angeles Times ● Aug. 18, 2026
Canada's Prime Minister Mark Carney has held urgent talks with US President Donald Trump, Ottawa confirmed Tuesday, in an effort to avoid fresh US tariffs on Canadian goods as a midnight deadline fast approaches.
From Barron's ● Aug. 18, 2026
I ask as fast as I can, like ripping off a Band-Aid.
From "Legendary Frybread Drive-In" by Cynthia Leitich Smith
It also features fewer components and more efficient assembly, which the company says makes it faster to deploy.
From MarketWatch ● Aug. 19, 2026
A recent study , externalfound the UK is likely to experience faster transitions between droughts and floods, especially in south-east England and parts of the north-west of the country.
From BBC ● Aug. 18, 2026
If you’re wondering how quickly to respond to inquires from recruiters and hiring managers, a new study suggests the faster the better.
From The Wall Street Journal ● Aug. 18, 2026
The Ebola outbreak in the Democratic Republic of Congo is moving faster than any previous epidemic of the disease and risks spreading to more countries, the head of the World Health Organization warned Tuesday.
From Barron's ● Aug. 18, 2026
It’s not that I don’t want to see him, it’s just that it’ll be faster to get through the paperwork if I have the place to myself.
From "Red Flags and Butterflies" by Sheryl Azzam
“It lets us build more dynamic, immersive experiences. In the cockpit of the fastest hunk of junk in the galaxy, that now means Unreal Engine 5 delivers a more responsive, cinematic experience than ever before.”
From Los Angeles Times ● Aug. 17, 2026
The outbreak was already the fastest growing on record, UN humanitarian chief Tom Fletcher said last week, warning that "the epidemic is killing someone every 30 minutes".
From BBC ● Aug. 17, 2026
The SHO made its debut in 1989 as the fastest front-wheel-drive car in the world.
From The Wall Street Journal ● Aug. 16, 2026
When he was pulled after just five innings and 65 pitches against the Marlins on Tuesday night, his fastest pitch was just 96.5 mph.
From The Wall Street Journal ● Aug. 14, 2026
After a short conversation, Clare had learned that the turtle spent his life as a beaver’s apprentice, and while he’d never been the fastest builder in the pond, he’d been the most diligent.
From "The Undead Fox of Deadwood Forest" by Aubrey Hartman
Sriramulu, a quiet Gandhian who had already undertaken several fasts for social causes, believed only self-sacrifice could force Delhi to listen.
From BBC ● Jul. 16, 2026
Other recent studies on prolonged fasting have also found that the body enters a deep ketogenic state during multi day fasts, dramatically changing how cells use fuel.
From Science Daily ● May 17, 2026
Six Flags Qiddiya City recently hosted iftar celebrations that marked the end of the daily Ramadan fasts.
From The Wall Street Journal ● Mar. 26, 2026
In the following years, they built a flourishing movement fighting for farmworkers’ rights, employing marches, fasts and other nonviolent protest actions.
From Los Angeles Times ● Mar. 19, 2026
He was a silent, brooding man, given to fasts and contemplation, going often, alone, into the caves of the mountains, in the section of Virginia where he lived.
From "Harriet Tubman: Conductor on the Underground Railroad" by Ann Petry
Wangchuk fasted in scorching heat in the capital, Delhi, for 26 days in June and July, consuming only salt and water.
From BBC ● Aug. 5, 2026
He said that he did go to the mosque every Friday, and that he prayed and fasted and raised his children to be good Muslims.
From Slate ● Apr. 19, 2026
These individuals typically ate their first meal after 14:00 and fasted for about 17 hours.
From Science Daily ● Apr. 11, 2026
In came the resistance bands, dead lifts, dumbbells and agility drills, plus a private chef who got a sweet break from 8 p.m. until noon the next day, as Doncic intermittently fasted.
From The Wall Street Journal ● Sep. 16, 2025
They isolated themselves and fasted for a while.
From "Lost Boy, Lost Girl" by John Bul Dau
In late 2022, Elon Musk posted that he lost 30 pounds by fasting and taking semaglutide.
From MarketWatch ● Aug. 5, 2026
People who lowered their protein intake lost weight and body fat and showed improvements in fasting blood sugar, despite often consuming more total calories.
From Science Daily ● Aug. 2, 2026
"Fasting, or controlled deprivation of food, is linked to a longer and healthier lifespan," says Dr Longo, who has spent three decades studying the effects of fasting.
From BBC ● Jul. 25, 2026
India's activist Sonam Wangchuk has ended a hunger strike after 26 days of fasting in support of youth-led protesters demanding education reforms.
From BBC ● Jul. 23, 2026
He would have been fasting for months while waiting for the sea ice to re-form, but he was still twice as big as the bear that had wrecked them before.
From "Two Degrees" by Alan Gratz
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
