资料来源 : pyDict

快速,无常

资料来源 : Webster's Revised Unabridged Dictionary (1913)

Fleetness \Fleet"ness\, n.
   Swiftness; rapidity; velocity; celerity; speed; as, the
   fleetness of a horse or of time.

资料来源 : WordNet®

fleetness
     n : rapidity of movement; "fleetness of foot"