Source : Webster's Revised Unabridged Dictionary (1913)

Decoy \De*coy"\ (d[-e]*koi"), v. t. [imp. & p. p. {Decoyed}; p.
   pr. & vb. n. {Decoying}.] [Pref. de- + coy; orig., to quiet,
   soothe, caress, entice. See {Coy}.]
   To lead into danger by artifice; to lure into a net or snare;
   to entrap; to insnare; to allure; to entice; as, to decoy
   troops into an ambush; to decoy ducks into a net.

         Did to a lonely cot his steps decoy.     --Thomson.

         E'en while fashion's brightest arts decoy, The heart,
         distrusting, asks if this be joy.        --Goldsmith.

   Syn: To entice; tempt; allure; lure. See {Allure}.

Decoy \De*coy"\, n.
   1. Anything intended to lead into a snare; a lure that
      deceives and misleads into danger, or into the power of an
      enemy; a bait.

   2. A fowl, or the likeness of one, used by sportsmen to
      entice other fowl into a net or within shot.

   3. A place into which wild fowl, esp. ducks, are enticed in
      order to take or shoot them.

   4. A person employed by officers of justice, or parties
      exposed to injury, to induce a suspected person to commit
      an offense under circumstances that will lead to his
      detection.

Source : WordNet®

decoy
     n 1: a beguiler who leads someone into danger (usually as part of
          a plot) [syn: {steerer}]
     2: something used to lure victims into danger [syn: {bait}, {lure}]
     v : lure or entrap with or as if with a decoy