/ Dictionary / Index D delusion: Meaning and Definition of Find definitions for: de•lu•sion Pronunciation: (di-l'zhun), [key] — n. an act or instance of deluding. the state of being deluded. a false belief or opinion: delusions of grandeur. a fixed false belief that is resistant to reason or confrontation with actual fact: a paranoid delusion. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: delusion (Thesaurus) deluge delusive Related Content Daily Word Quiz: reclusive Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language