Source : Webster's Revised Unabridged Dictionary (1913)

Cloven \Clo"ven\, p. p. & a.
   from {Cleave}, v. t.

   {To show the cloven foot} or {hoof}, to reveal a devilish
      character, or betray an evil purpose, notwithstanding
      disguises, -- Satan being represented dramatically and
      symbolically as having cloven hoofs.