The Collaborative International Dictionary of English v.0.48:

Tawny \Taw"ny\, a. [Compar. Tawnier; superl. Tawniest.] [F.
   tann['e], p. p. of tanner to tan. See Tan, v. t. & n. Cf.
   Tenn['e].]
   Of a dull yellowish brown color, like things tanned, or
   persons who are sunburnt; as, tawny Moor or Spaniard; the
   tawny lion. "A leopard's tawny and spotted hide."
   --Longfellow.
   [1913 Webster]