The Collaborative International Dictionary of English v.0.48:

Illusionist \Il*lu"sion*ist\, n.
   1. One given to illusion; a visionary dreamer.
      [1913 Webster]

   2. A magician or conjurer who produces illusions by sleight
      of hand; a prestidigitator.
      [PJC]

WordNet (r) 3.0 (2006):

illusionist
    n 1: a person with unusual powers of foresight [syn:
         visionary, illusionist, seer]
    2: someone who performs magic tricks to amuse an audience [syn:
       magician, prestidigitator, conjurer, conjuror,
       illusionist]

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "illusionist":
   Merlin, Prospero, airiness, appearance, conjurer, delusiveness,
   escamoteur, fallaciousness, false appearance, false light,
   false show, falseness, idealization, illusionism, illusiveness,
   immateriality, juggler, mage, magian, magic, magic act, magic show,
   magician, magus, prestidigitation, prestidigitator, seeming,
   semblance, show, simulacrum, sleight of hand,
   sleight-of-hand performer, sorcerer, sorcery, specious appearance,
   tricker, trickster, unactuality, unreality, unsubstantiality