The Collaborative International Dictionary of English v.0.48:

Race \Race\, v. i. [imp. & p. p. Raced (r[=a]st); p. pr. & vb.
   n. Racing (r[=a]"s[i^]ng).]
   1. To run swiftly; to contend in a race; as, the animals
      raced over the ground; the ships raced from port to port.
      [1913 Webster]

   2. (Steam Mach.) To run too fast at times, as a marine engine
      or screw, when the screw is lifted out of water by the
      action of a heavy sea.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Racing \Ra"cing\ (r[=a]"s[i^]ng),
   a. & n. from Race, v. t. & i.
   [1913 Webster]

   Racing crab (Zool.), an ocypodian.
      [1913 Webster]

WordNet (r) 3.0 (2006):

racing
    n 1: the sport of engaging in contests of speed

Moby Thesaurus II by Grady Ward, 1.0:

31 Moby Thesaurus words for "racing":
   affluent, automobile racing, confluent, coursing, decurrent,
   defluent, diffluent, dog racing, flowing, fluent, fluxional,
   fluxive, gulfy, gushing, horse racing, mazy, meandering, pouring,
   profluent, running, rushing, serpentine, sluggish, streaming,
   surging, surgy, the turf, tidal, track, track sports, vortical