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.