Source : Webster's Revised Unabridged Dictionary (1913)

Stalking-horse \Stalk"ing-horse\, n.
   1. A horse, or a figure resembling a horse, behind which a
      hunter conceals himself from the game he is aiming to
      kill.

   2. Fig.: Something used to cover up a secret project; a mask;
      a pretense.

            Hypocrisy is the devil's stalking-horse under an
            affectation of simplicity and religion.
                                                  --L'Estrange.

            How much more abominable is it to make of him
            [Christ] and religion a stalking-horse, to get and
            enjoy the world!                      --Bunyan.

Source : WordNet®

stalking-horse
     n 1: a candidate put forward to divide the opposition or to mask
          the true candidate
     2: something serving to conceal plans; a fictitious reason that
        is concocted in order to conceal the real reason [syn: {pretext}]
     3: screen consisting of a figure of a horse behind which a
        hunter hides while stalking game
     4: a horse behind which a hunter hides while stalking game