The Collaborative International Dictionary of English v.0.48:

Cheater \Cheat"er\, n.
   1. One who cheats.
      [1913 Webster]

   2. An escheator. [R.] --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

cheater
    n 1: someone who leads you to believe something that is not true
         [syn: deceiver, cheat, cheater, trickster,
         beguiler, slicker]