rapid

Very swift or quick.

a rapid stream

rapid growth

Steep, changing altitude quickly. (of a slope)

Needing only a brief exposure time. (of a lens, plate, film, etc.)

Violent, severe.

Happy.

Rapidly.

A rough section of a river or stream which is difficult to navigate due to the swift and turbulent motion of the water.

A burst of rapid fire.

Ellipsis of rapid chess.

In these rapid games we had just twenty-five minutes each to make all our moves, a far cry from traditional chess, where games can last up to seven hours.

In order to avoid misunderstanding, I must note that I object to the attempts to displace normal chess with fast play, not rapid or blitz in general. I love them both, and, if I were to choose which to play, classic or rapid, I would choose rapid.