Source : Webster's Revised Unabridged Dictionary (1913)

Tormenter \Tor*ment"er\, n.
   1. One who, or that which, torments; a tormentor.

   2. An executioner. [Obs.] --Chaucer.

Source : WordNet®

tormenter
     n 1: someone who torments [syn: {tormentor}, {persecutor}]
     2: a flat at each side of the stage to prevent the audience
        from seeing into the wings [syn: {tormentor}, {teaser}]