[ fast, fahst ]
/ fæst, fɑst /
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See synonyms for: fast / faster / fastest / fasting on Thesaurus.com

adjective, fast·er, fast·est.

adverb, fast·er, fast·est.


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



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On the farm, the feed for chicks is significantly different from the roosters’; ______ not even comparable.

Idioms for fast

    play fast and loose. play (def. 80).
    pull a fast one, Informal. to play an unfair trick; practice deceit: He tried to pull a fast one on us by switching the cards.

Origin of fast

First recorded before 900; Middle English; Old English fæst “firm”; cognate with Dutch vast, Old Norse fastr “firm,” German fest; akin to fast2
1, 2. See quick.

Definition for fast (2 of 3)

[ fast, fahst ]
/ fæst, fɑst /

verb (used without object)

to abstain from all food.
to eat only sparingly or of certain kinds of food, especially as a religious observance.

verb (used with object)

to cause to abstain entirely from or limit food; put on a fast: to fast a patient for a day before surgery.


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.

Origin of fast

First recorded before 1000; Middle English fasten, festen, Old English fæstan; cognate with German fasten, Gothic fastan, Old Norse fasta
un·fast·ing, adjective

Definition for fast (3 of 3)

[ fast, fahst ]
/ fæst, fɑst /


a chain or rope for mooring a vessel.

Origin of fast

First recorded in 1670–80; alteration, by association with fast1 (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, fast1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

British Dictionary definitions for fast (1 of 2)

/ (fɑːst) /




archery (said by the field captain to archers) stop shooting!
Old English fæst strong, tight; related to Old High German festi firm, Old Norse fastr

British Dictionary definitions for fast (2 of 2)

/ (fɑːst) /


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


  1. an act or period of fasting
  2. (as modifier)a fast day
faster, noun
Old English fæstan; related to Old High German fastēn to fast, Gothic fastan
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for fast (1 of 2)

fast 11
[ făst ]


Acting, moving, or being capable of acting or moving quickly.
Accomplished in relatively little time.
Exhibiting resistance to change. Used especially of stained microorganisms that cannot be decolorized.
Firmly fixed or fastened.

Medical definitions for fast (2 of 2)

fast 22
[ făst ]


To abstain from food.
To eat little or abstain from certain foods, especially as a religious discipline.


The act or practice of abstaining from or eating very little food.
A period of such abstention or self-denial.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Idioms and Phrases with fast


The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
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