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fast

/fɑːst/
IELTSAcademic
adjective

Moving or happening at a high speed. It can also mean quick to do something.

  • That car is very fast.
  • She is a fast runner.
  • We need a fast answer.
adverb

With great speed. In modern English, this is less common than the adjective form.

  • He runs fast.
  • The river flowed fast.
  • Please speak fast and clearly.
noun

A period when you do not eat food, often for religious or health reasons.

  • She kept a fast for two days.
  • The fast ended at sunset.
  • He is on a water fast.
verb

To stop eating food for a period of time.

  • They fast during the festival.
  • I fast on Fridays.
  • Some people fast for health reasons.

Adinary Nuance

Fast is more general than quick. Use fast for speed itself, like a fast car or fast internet. Quick often focuses on short time or prompt action, like a quick reply or quick lunch. Rapid is more formal and common in writing.

In other languages

Vietnamese
nhanh
Spanish
rápido
Chinese
Japanese
速い
Korean
빠른

Etymology

Old English fast, from Proto-Germanic *fastuz, meaning 'firm' or 'fixed'. The meaning 'not moving' later developed into 'quickly' and 'without delay'.

Common phrases

fast foodfast lanefast-movingfast train

Synonyms

Related words

Frequently asked questions

Is fast more common than quick?
Yes, especially for speed, vehicles, and internet connection.
What is the difference between fast and quick?
Fast means high speed. Quick often means done in little time.
Can fast be a noun?
Yes. It means a period of not eating food.
Is fast used in formal writing?
Yes, but rapid is often more formal in reports and academic writing.