Source : Webster's Revised Unabridged Dictionary (1913)

Degenerative \De*gen"er*a*tive\, a.
   Undergoing or producing degeneration; tending to degenerate.

Source : WordNet®

degenerative
     adj : of illness; marked by gradual deterioration of organs and
           cells along with loss of function; "degenerative
           diseases of old age"