delusion

noun

1
the act of deluding; deception by creating illusory ideas
2
a mistaken or unfounded opinion or idea
he has delusions of competence
his dreams of vast wealth are a hallucination
3
(psychology) an erroneous belief that is held in the face of evidence to the contrary

Also useful for “delusion”:Unscrambler— Rearrange the letters in “delusion”