swift

/ˈswift/

Middle English, from Old English; akin to Old English swīfan to revolve

adjective

  1. moving or capable of moving with great speed

  2. occurring suddenly or within a very short time

  3. quick to respond : ready

a swift runner

fast rapid swift fleet quick speedy hasty expeditious mean moving, proceeding, or acting with celerity. fast and rapid are very close in meaning, but fast applies particularly to the thing that moves and rapid to the movement itself.

adverb

  1. swiftly

swift-flowing

noun

  1. any of several lizards (especially of the genus Sceloporus) that run swiftly

  2. a reel for winding yarn or thread

  3. any of numerous small plainly colored birds (family Apodidae) that are related to the hummingbirds but superficially much resemble swallows