illusion in WordNet English dictionary

1. an illusory feat; considered magical by naive observers
   magic trick  conjuring trick  trick  magic  legerdemain  conjuration  thaumaturgy  illusion  deception 
   
2. the act of deluding; deception by creating illusory ideas
   delusion  illusion  head game 
   
3. something many people believe that is false
   "they have the illusion that I am very wealthy"
   illusion  fantasy  phantasy  fancy 
   
4. an erroneous mental representation
   illusion  semblance