The Collaborative International Dictionary of English v.0.48:

Foussa \Fous"sa\, n. [Natibe name.] (Zool.)
   A viverrine animal of Madagascar (Cryptoprocta ferox). It
   resembles a cat in size and form, and has retractile claws.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Cryptoprocta ferox
    n 1: largest carnivore of Madagascar; intermediate in some
         respects between cats and civets [syn: fossa, fossa
         cat, Cryptoprocta ferox]