Rapid

Webster's Dictionary of the English Language

·adj Quick in execution; as, a rapid penman.

II. Rapid ·adj Very swift or quick; moving with celerity; fast; as, a rapid stream; a rapid flight; a rapid motion.

III. Rapid ·adj Advancing with haste or speed; speedy in progression; in quick sequence; as, rapid growth; rapid improvement; rapid recurrence; rapid succession.

IV. Rapid ·adj The part of a river where the current moves with great swiftness, but without actual waterfall or cascade;

— usually in the plural; as, the Lachine rapids in the St. Lawrence.