Source : Webster's Revised Unabridged Dictionary (1913)

Unau \U*nau"\, n. [Brazilian.] (Zo["o]l.)
   The two-toed sloth ({Cholopus didactylus}), native of South
   America. It is about two feet long. Its color is a uniform
   grayish brown, sometimes with a reddish tint.

Source : WordNet®

unau
     n 1: relatively small fast-moving sloth [syn: {two-toed sloth}, {Choloepus
          hoffmanni}]
     2: relatively small fast-moving sloth [syn: {two-toed sloth}, {Choloepus
        didactylus}]