Source : Webster's Revised Unabridged Dictionary (1913)

Mocker \Mock"er\, n.
   1. One who, or that which, mocks; a scorner; a scoffer; a
      derider.

   2. A deceiver; an impostor.

   3. (Zo["o]l.) A mocking bird.

   {Mocker nut} (Bot.), a kind of hickory ({Carya tomentosa})
      and its fruit, which is far inferior to the true shagbark
      hickory nut.

Source : WordNet®

mocker
     n 1: someone who jeers or mocks or treats something with contempt
          or calls out in derision [syn: {scoffer}, {flouter}, {jeerer}]
     2: long-tailed gray-and-white songbird of the southern United
        States able to mimic songs of other birds [syn: {mockingbird},
         {Mimus polyglotktos}]