1
2
: firmly loyal
became fast friends
3
a
: characterized by quick motion, operation, or effect:
(1)
: moving or able to move rapidly : swift
a fast horse
(2)
: taking a comparatively short time
a fast race
(3)
: imparting quickness of motion
a fast bowler
(4)
: accomplished quickly
fast work
(5)
: agile of mind
especially
: quick to learn
a class for fast students
b
: conducive to rapidity of play or action
a fast track
c(1)
of a timepiece or weighing device
: indicating in advance of what is correct
Your clock is two minutes fast.
(2)
: according to or being daylight saving time
d
: contributing to a shortening of exposure time
fast film
e
: acquired with unusually little effort and often by shady or dishonest methods
had a keen eye for a fast buck—
R. A. Keith
R. A. Keith4
a
: securely attached
a rope fast to the wharf
b
: tenacious
a fast hold on her purse
5
a
archaic
: sound asleep
b
of sleep
: not easily disturbed
fell into a fast sleep
6
: not fading or changing color readily
fast colors
7
a
: actively seeking excitement and pleasure : wild
a pretty fast crowd
b
: sexually promiscuous
8
: resistant to change (as from destructive action or fading)
fast dyes
—often used in combinationsunfast
acid-fast bacteria
fasted; fasting; fasts
Synonyms
Examples of fast in a Sentence
Adjective
She's a very fast runner.
We're off to a fast start.
We're now experiencing a faster rate of inflation.
We took the faster route.
Adverb
The boss expects this to be done this afternoon, so you'd better work fast.
He ran as fast as he could.
This is fast becoming a national problem.
You need to act fast to take advantage of this offer.
I don't know what caused the accident. It all happened so fast.
She's a woman who can think fast in a crisis.
He's going to have to talk fast to get himself out of this mess.
The window was stuck fast.
She held fast to her belief in justice.
We must stand fast and not surrender!
Verb
She always fasts on Yom Kippur.
Patients must fast for six hours before having the procedure.
Recent Examples on the Web
Alex Veiga, The Denver Post, 15 Nov. 2024
The Food and Drug Administration said in an update that the number of people sickened by the fast food bacteria outbreak has climbed from 90 to 104.
—Melvin Backman, Quartz, 14 Nov. 2024
Abigail Wise, Outside Online, 16 Nov. 2024
Unfortunately, policy rarely moves faster than science.
—Lara Williams, The Mercury News, 15 Nov. 2024
Danny Emerman, The Mercury News, 17 Oct. 2024
Speech fasting, also known as vocal rest or voice fasting, is intentionally not speaking for some time.
—Dominique Fluker, Essence, 15 Oct. 2024
Bob Holmes, Smithsonian Magazine, 9 Oct. 2024
These fasts are ideal for busy individuals seeking a more flexible fasting schedule who want to lose weight and improve their health.
—Elizabeth Barnes, Verywell Health, 19 Oct. 2024
See all Example Sentences for fast 
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show current usage.
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Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
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Adjective
Last week, bond yields surged on expectations that President-elect Donald Trump’s plans to lower tax rates, increase tariffs and reduce regulation could ultimately lead to higher U.S. government debt and inflation, along with faster economic growth.
—Alex Veiga, The Denver Post, 15 Nov. 2024
The Food and Drug Administration said in an update that the number of people sickened by the fast food bacteria outbreak has climbed from 90 to 104.
—Melvin Backman, Quartz, 14 Nov. 2024
Adverb
Buy from Patagonia For the Yogi Hugger Mugger Yoga Wipes
Nothing throws off a practice faster than a stinky mat.
—Abigail Wise, Outside Online, 16 Nov. 2024
Unfortunately, policy rarely moves faster than science.
—Lara Williams, The Mercury News, 15 Nov. 2024
Verb
Working with a nutritionist, Looney fasted until roughly 4 or 5 p.m., going through his morning and afternoon workouts — sprints, lifting, 5-on-5 work — on just a cup of coffee.
—Danny Emerman, The Mercury News, 17 Oct. 2024
Speech fasting, also known as vocal rest or voice fasting, is intentionally not speaking for some time.
—Dominique Fluker, Essence, 15 Oct. 2024
Noun
Do a metabolic flip By the end of its nightly fast, a hummingbird has nearly depleted its sugar stores—which poses an opposite metabolic challenge.
—Bob Holmes, Smithsonian Magazine, 9 Oct. 2024
These fasts are ideal for busy individuals seeking a more flexible fasting schedule who want to lose weight and improve their health.
—Elizabeth Barnes, Verywell Health, 19 Oct. 2024
See all Example Sentences for fast
Articles Related to fast
Dictionary Entries Near fast
Cite this Entry
“Fast.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fast. Accessed 1 Dec. 2024.
Copy CitationKids Definition
fast
1 of 4 adjective1
a
: firmly fixed or bound
b
: tightly shut
c
: sticking firmly
2
: firmly loyal
became fast friends
3
a
: moving or able to move rapidly
b
: taking a short time
c
: giving quickness of motion (as to a thrown ball)
d
: favorable to speed
the faster route
4
: indicating ahead of the correct time
my clock is fast
5
: tricky and unfair
pulled a fast one
6
: not likely to fade
fast colors
fast
3 of 4 verb1
: to go without eating
2
: to eat in small amounts or only certain foods
fast
4 of 4 noun1
: the act of fasting
2
: a time of fasting
Etymology
Adjective
Old English fæst "firmly fixed"
Verb
Old English fæstan "to go without eating"
Medical Definition
fast
1 of 3 adjective1
: firmly fixed
2
a
: having a rapid effect
a fast medicine
b
: allowing for the rapid passage of a gas or liquid
3
: resistant to change (as from destructive action)
—used chiefly of organisms and in combination with the agent resisted
acid-fast bacteria
fast
2 of 3 intransitive verb1
: to abstain from food
2
: to eat sparingly or abstain from some foods
: to deny food to
the patient is fasted and given a mild hypnotic—Lancet
Lancetfast
3 of 3 noun1
: the practice of fasting
2
: a time of fasting
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