迅速,敏捷
Swiftness \Swift"ness\, n. The quality or state of being swift; speed; quickness; celerity; velocity; rapidity; as, the swiftness of a bird; the swiftness of a stream; swiftness of descent in a falling body; swiftness of thought, etc.
swiftness n : a rate (usually rapid) at which something happens; "the project advanced with gratifying speed" [syn: {speed}, {fastness}]