The Collaborative International Dictionary of English v.0.48:

Vulpine \Vul"pine\ (?; 277), a. [L. vulpinus, from vulpes a
   fox.]
   Of or pertaining to the fox; resembling the fox; foxy;
   cunning; crafty; artful.
   [1913 Webster]

   Vulpine phalangist (Zool.), an Australian carnivorous
      marsupial (Phalangista vulpina syn. Trichosurus
      vulpina); -- called also vulpine phalanger, and
      vulpine opossum.
      [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "vulpine":
   Machiavellian, Machiavellic, acute, arch, artful, astute, cagey,
   canine, canny, clever, crafty, cunning, cute, deceitful, deep,
   deep-laid, designing, diplomatic, doggy, feline, foxlike, foxy,
   guileful, ingenious, insidious, inventive, knowing, lupine, pawky,
   politic, ready, resourceful, scheming, serpentine, sharp, shifty,
   shrewd, slick, slippery, sly, smooth, snaky, sneaky, sophistical,
   stealthy, strategic, subtile, subtle, supple, tactical, trickish,
   tricksy, tricky, wary, wily, wolfish