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Definitions

delusion

[dih-loo-zhuhn] / dɪˈlu ʒən /
NOUN
misconception, misbelief
Synonyms
STRONGEST
deception fantasy hallucination illusion pipe dream
STRONG
apparition blunder casuistry chicanery daydream deceptiveness dream error fallacy fancy figment ghost lapse mirage misapprehension mistake oversight phantasm phantom self-deception shade speciousness spuriousness trickery trip vision
WEAK
eidolon false impression fool's paradise head trip ignis fatuus optical illusion
Antonyms
STRONGEST
fact reality truth
STRONG
accuracy actuality being certainty correction fix honesty right success
WEAK
surety

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

It unofficially formed in a Reddit chatroom last June for users who’ve experienced “spiraling” from A.I. delusion themselves or who’ve tried to help friends and family out.

From Slate • Feb. 2, 2026

A U.K. police chief is under fire after admitting a delusion from Microsoft Copilot produced incorrect evidence.

From MarketWatch • Jan. 14, 2026

“We might have had the delusion of a reprieve. But they didn’t change their mind.”

From Los Angeles Times • Jan. 2, 2026

For heavyweight great Lennox Lewis, however, that confidence edges into "delusion".

From BBC • Dec. 19, 2025

Maybe the life I think I’m living is a paranoid delusion.

From "The Handmaid's Tale" by Margaret Atwood

From Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.