Main entry: illusion, head game, delusion
Definition: the act of deluding; deception by creating illusory ideas
Main entry: hallucination, delusion
Definition: a mistaken or unfounded opinion or idea
Usage: he has delusions of competence; his dreams of vast wealth are a hallucination
Main entry: psychotic belief, delusion
Definition: (psychology) an erroneous belief that is held in the face of evidence to the contrary