lycanthrope

from WordNet (r) 3.0 (2006)

lycanthrope
    n 1: a monster able to change appearance from human to wolf and
         back again [syn: {werewolf}, {wolfman}, {lycanthrope},
         {loup-garou}]

from The Collaborative International Dictionary of English v.0.48

Lycanthrope \Ly"can*thrope\, n. [Gr. ?; ? a wolf + ? a man.]
   1. A human being fabled to have been changed into a wolf; a
      werewolf.
      [1913 Webster]

   2. One affected with lycanthropy.
      [1913 Webster]