Source : Webster's Revised Unabridged Dictionary (1913)

Numbness \Numb"ness\, n.
   The condition of being numb; that state of a living body in
   which it loses, wholly or in part, the power of feeling or
   motion.

Source : WordNet®

numbness
     n : partial or total lack of sensation in a part of the body; a
         symptom of nerve damage or dysfunction