Definitions
1.AdjectiveVery swift or quick."a rapid stream; rapid growth; rapid improvement"
2.AdjectiveSteep, changing altitude quickly. (of a slope)
3.AdjectiveNeeding only a brief exposure time. (of a lens, plate, film, etc.)
4.AdjectiveViolent, severe.
5.AdjectiveHappy.
6.AdverbRapidly.
7.NounA rough section of a river or stream which is difficult to navigate due to the swift and turbulent motion of the water.
8.NounA burst of rapid fire.
9.NounEllipsis of rapid chess.