fast

FAST/fæst/FAHST/fɑːst/

Adjectivefaster, fastest

Adverbfaster, fastest

Verbfasts, fasting, fasted

Noun pluralfasts

21 meanings of fast

Practice

1
high speedadjective
Moving or working very quickly.
Like a race car speeding down a track.
The fast train reached the next city in under an hour.
He is the fastest runner on the whole team.
UsageSay a fast car, but a quick look.
Similarquick, rapid, swift, speedy, brisk
Oppositeslow, sluggish
Note
2
adverb
Quickly, in a way that takes very little time.
Like a light turning on the moment you flip the switch.
Don't eat so fast or you'll get a stomachache.
The fire spread fast through the dry grass.
UsageSay run fast, with no -ly.
Similarquickly, rapidly, swiftly, speedily
Oppositeslowly
3
go without foodverbintransitive
To not eat for a time, because of religion or health.
Like choosing not to eat all day on purpose.
Many adults fast during the holy month.
She fasts one day each week as part of her faith.
UsageSay fast for a day.
Oppositefeast, eat
Note
4
food abstinencenouncountable
A time when you do not eat, often for religious reasons.
Like deciding not to eat for a set time on purpose.
They began their fast at sunrise.
The fast lasted three full days.
UsageYou keep a fast, then break it by eating.
Oppositefeast
Note
5
hecticadjective
Full of activity, with lots of people busy and moving around.
Like a busy train station where everyone is rushing around.
The capital is a fast city, with busy streets day and night.
After a week in the fast, crowded city, we were glad to get home.
Similarbusy, hectic, bustling, frenetic, lively
Oppositequiet, sleepy, slow, tranquil

Less common meanings

6
a deep sleepadjectivearchaic
So deep that a person is hard to wake, said of sleep.
Similardeep, sound
Oppositelight
Note
7
tightlyadverb
In a firm, tight way so that something cannot move.
Like glue holding two pieces of paper together.
Hold fast to the rope while we pull you up.
The lid was stuck fast and would not open.
UsageHold fast means hold tightly. Stuck fast means it won't move.
Similarsecurely, firmly, tightly
Oppositeloosely
Note
8
clock aheadadjective
Showing a later time than the real time, as a clock does.
Like a clock that thinks it is later than it really is.
My watch is ten minutes fast.
The wall clock looks fast compared to my phone.
UsageSay my watch is five minutes fast.
Similarahead
Oppositebehind, slow
Note
9
adverb
In a way that shows a time ahead of the real time.
This old clock always runs fast.
If your watch runs fast, you'll get to every meeting too early.
Similarahead
Oppositebehind
10
sleep soundlyadverb
In a deep, sound way, said of sleeping.
Like sleeping so deeply that a loud bell can't wake you.
The baby was fast asleep before the song ended.
By the time we got home, the kids were fast asleep in the back seat.
UsageFast asleep means sleeping deeply.
Similardeeply
Oppositelightly
Note
11
loyaladjective
Loyal and not changing in feeling, as a close friend.
Like a friendship that stays strong no matter what happens.
They have been fast friends since childhood.
The two remained fast allies through every hardship.
Similarfirm, close, loyal, steadfast, staunch
Oppositefickle, disloyal, inconstant
Note
12
not fadingadjective
Not fading or washing out when wet or in bright light.
Like a permanent marker that doesn't smear when it gets wet.
This dye is fast, so the shirt won't fade in the wash.
Choose a fast ink that holds up in sunlight.
Similarpermanent, fixed, indelible, stable, lasting
Oppositefugitive, impermanent
Note
13
quick surfaceadjective
Making a game or action happen more quickly than usual.
The new track is fast, so the cars reach top speed quickly.
Players love this fast court because the ball moves so quickly.
Similarquick, slick
Oppositeslow
14
light-sensitiveadjective
For camera film, needing only a little light, or for a lens, opening wide to let in lots of light.
A fast lens lets you take clear pictures even in a dark room.
She loaded fast film to capture the dim stage performance.
Similarsensitive, high-speed, bright
Oppositeslow
Note
15
adjectivedated
Held tightly in place and hard to move.
Like a nail hammered deep into wood that won't pull out.
Make the rope fast before the boat drifts away.
Make sure the tent pegs are fast in the ground.
UsageMake a rope fast means tie it tightly.
Similarsecure, firm, fixed, tight, immovable
Oppositeloose, insecure
16
wild livingadjectivedated
Old-fashioned: living a wild life with too much fun, money, or sex.
He was known as a fast young man who spent money on parties.
You're alone with her at last / And you're waiting 'til you think the time is right / Cause you've heard she's pretty fast / And you're hoping that she'll give you some tonight.
1979, Doug Fieger, Good Girls Don'tHere, fast means wild and sexually free, willing to have sex easily.
Similarwild, dissolute, loose
Note
17
close behindadverb
Very close to something, or coming right after it in place or time.
Fast on the heels of the rain came a bright, warm morning.
A cold snap followed fast on the heels of the warm spell.
Similarclose, hard, near, right
Oppositefar
Note
18
nounBritishcountable
A train that stops only at the bigger stations, not at every one.
Like an express bus that only stops at the main places.
Take the fast if you want to reach the city without lots of stops.
The fast skips all the small village stations.
Similarexpress
Oppositelocal
Note
19
verb
To make a person or animal go without food for a time.
20
adjective
Of a neutron, moving very quickly and carrying high energy right after a nuclear reaction.
21
interjection
A word shouted on an archery range to make everyone stop shooting at once. Short for stand fast.

Practice

Can you tell the meanings of fast apart? Answer 3 quick questions from this page, or write your own sentence and AI will check it.

Origins

Meanings 1, 5–6, 8, 11–16, 18

From Old English fæst, meaning "firm" or "secure." The meaning "rapid" came later, first in the adverb.

Checked 1 Nov 2026 · 2 facts

Fast derives from Old English fæst, meaning firm or secure. en.wiktionary.org
The rapid sense developed later, first in the adverb. en.wiktionary.org

Meanings 2, 7, 9–10, 17

From Old English fæste, formed from fæst plus the adverb ending -e.

Checked 1 Nov 2026 · 2 facts

The adverb fast derives from Old English fæste. en.wiktionary.org
Old English fæste was formed from fæst with the adverb-forming suffix -e. en.wiktionary.org

Meanings 3–4

From Old English fæstan (verb) and fæsten (noun), the verb from Proto-Germanic *fastāną, related to Etymology 1. The religious sense of "going without food" likely came from the Gothic church, where the word meant "hold fast" to the rule of abstinence.

Checked 1 Nov 2026 · 5 facts

The verb fast descends from Old English fæstan. en.wiktionary.org
The noun fast descends from Old English fæsten. en.wiktionary.org
Old English fæstan, meaning to fast, derives from Proto-Germanic *fastāną. en.wiktionary.org
The fasting verb shares its root with fast meaning firm or fixed, covered by Etymology 1. en.wiktionary.org
The religious sense is conjectured to have originated in the Gothic church through holding fast to the rule of abstinence. en.wiktionary.org