rapid

/ˈra-pəd/

borrowed from French & Latin; French rapide, going back to Middle French, borrowed from Latin rapidus "(of water) flowing violently enough to sweep anything along in its path, swiftly moving, quick," from rapere "to seize and carry off, carry or sweep along" + -idus, adjective suffix; rapere perhaps going back to pre-Latin *rp-, secondary zero-grade from presumed *erp-, going back to Indo-European *hrp-, zero-grade of a base *hrep- "seize, pluck," whence also Lithuanian aprė́piu, aprė́pti "to surround, include," Albanian rjep "removes, robs," Greek ereptómenos "feeding on, devouring"

adjective

  1. marked by a fast rate of motion, activity, succession, or occurrence

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.

noun

  1. a part of a river where the current is fast and the surface is usually broken by obstructions —usually used in plural but singular or plural in construction

noun

  1. a rapid conjugate movement of the eyes associated especially with REM sleep