- 1[usually before noun] happening in a short period of time rapid change/expansion/growth a rapid rise/decline in sales The patient made a rapid recovery.
- 2done or happening very quickly a rapid pulse/heartbeat The guard fired four shots in rapid succession. The disease is spreading at a rapid rate. Which Word?fast / quick / rapidThese adjectives are frequently used with the following nouns:
Fast is used especially to describe a person or thing that moves or is able to move at great speed. Quick is more often used to describe something that is done in a short time or without delay. Rapid, swift, and speedy are more formal words. Rapid is most commonly used to describe the speed at which something changes. It is not used to describe the speed at which something moves or is done:a rapid train We had a rapid coffee. Swift usually describes something that happens or is done quickly and immediately:a swift decision The government took swift action. Speedy has a similar meaning:a speedy recovery. It is used less often to talk about the speed at which something moves:a speedy car For the use of fast and quick as adverbs, see the usage note at quick.
fast ~ quick ~ rapid ~ car glance change train look growth runner reply increase pace decision decline lane way progress
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NAmE//rəˈpɪdət̮i//noun [uncountable] the rapidity of economic growth The disease is spreading with alarming rapidity.
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NAmE//ˈræpədli//adverb a rapidly growing economy Crime figures are rising rapidly.