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fast 1 (făst)
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adj. fast·er, fast·est
1. Acting, moving, or capable of acting or moving quickly; swift.
2.
a. Accomplished in relatively little time: a fast visit.
b. Acquired quickly with little effort and sometimes unscrupulously: made a fast buck scalping tickets.
3. Quick to understand or learn; mentally agile: a class for the faster students.
4. Indicating a time somewhat ahead of the actual time: The clock is fast.
5. Allowing rapid movement or action: a fast running track.
6. Designed for or compatible with a short exposure time: fast film.
7.
a. Disposed to dissipation; wild: ran with a fast crowd.
b. Flouting conventional moral standards; sexually promiscuous.
8. Resistant, as to destruction or fading: fast colors.
9. Firmly fixed or fastened: a fast grip.
10. Fixed firmly in place; secure: shutters that are fast against the rain.
11. Lasting; permanent: fast rules and regulations.
12. Deep; sound: in a fast sleep.
adv. faster, fastest
1. In a secure manner; tightly: hold fast.
2. To a sound degree; deeply: fast asleep.
3. In a rapid manner; quickly.
4. In quick succession: New ideas followed fast.
5. Ahead of the correct or expected time: a watch that runs fast.
6. In a dissipated, immoderate way: living fast.
7. Archaic Close by; near.
Idiom:
fast friend
A friend who is firm in loyalty: became fast friends after only knowing each other a few months.

[Middle English, from Old English fæst, firm, fixed; see past- in the Appendix of Indo-European roots.]

Synonyms: fast1, rapid, swift, fleet2, speedy, quick, expeditious
These adjectives refer to something marked by great speed. Fast and rapid are often used interchangeably, though fast is more often applied to the person or thing in motion, and rapid to the activity or movement involved: a fast runner; rapid strides. Swift suggests smoothness and sureness of movement (a swift current), and fleet, lightness of movement (The cheetah is the fleetest of animals). Speedy refers to velocity (a speedy train) or to promptness or hurry (a speedy resolution to the problem). Quick most often applies to what takes little time or to what is prompt: a quick snack; your quick reaction. Expeditious suggests rapid efficiency: sent the package by the most expeditious means. See Also Synonyms at faithful.

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2017 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 
fast 2 (făst)
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intr.v. fast·ed, fast·ing, fasts
1. To abstain from food.
2. To eat very little or abstain from certain foods, especially as a religious discipline.
n.
1. The act or practice of abstaining from or eating very little food.
2. A period of such abstention or self-denial.

[Middle English fasten, from Old English fæstan; see past- in the Appendix of Indo-European roots.]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2017 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 

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