definition of
[delusion]

[1] #1 delusion n. [psychotic belief] (psychology) an erroneous belief that is held in the face of evidence to the contrary. wn

[2] #2 delusion n. [hallucination] a mistaken or unfounded opinion or idea; "he has delusions of competence"; "his dreams of vast wealth are a hallucination". wn

[3] #3 delusion n. [illusion, head game] the act of deluding; deception by creating illusory ideas. wn