delusion

[dih-loo-zhuhn]

noun

1. an act or instance of deluding.

   Synonyms: deception

2. the state of being deluded.

3. a false belief or opinion.

   delusions of grandeur.

4. Psychiatry.,  a fixed false belief that is resistant to reason or confrontation with actual fact.

   a paranoid delusion.

delusion

/ dɪˈluːʒən, dɪˈluːsərɪ /

noun

1. a mistaken or misleading opinion, idea, belief, etc

   he has delusions of grandeur

2. psychiatry a belief held in the face of evidence to the contrary, that is resistant to all reason See also illusion hallucination

3. the act of deluding or state of being deluded

delusion

1. A false belief or perception strongly held in spite of invalidating evidence, especially as a symptom of mental illness, as in schizophrenia.

delusion

1. A false belief held despite strong evidence against it; self-deception. Delusions are common in some forms of psychosis. Because of his delusions, the literary character Don Quixote attacks a windmill, thinking it is a giant.

Other Word Forms

• delusional adjective
• delusionary adjective
• predelusion noun
• delusive adjective
• delusory adjective
• delusiveness noun
• delusively adverb

Word History and Origins

Origin of delusion¹

First recorded in 1375–1425; late Middle English, from Latin dēlūsiōn- (stem of dēlūsiō ), equivalent to dēlūs(us) (past participle of dēlūdere; delude ) + -iōn- -ion

Synonym Study

See illusion.

Example Sentences

MAGA’s stereotypes make for a perfect inversion of reality — especially because delusion is the state in which they need to live.

From Salon

Some of those clubs had a big claim on being the greatest European bogey that caused the most damage to Celtic and the delusions of grandeur they have of themselves as a great European club.

From BBC

But when Alice faces challenges, she lets go of her delusions.

From Los Angeles Times

Side effects related to the nervous system include hallucinations, delusions, depression, confusion and trouble breathing.

From Los Angeles Times

You'd need to be a person of unshakeable faith, laced with a glorious delusion, to think that Rangers, with all their defensive vulnerabilities, are going to turn this around in Belgium next week.

From BBC

Related Words

• deception 
• fantasy 
• hallucination 
• illusion 
• pipe dream 

When To Use

What is a delusion?

A delusion is a false belief or opinion, especially one held in resistance to strong evidence against it, as in Even after losing five straight championships, Heather still had the delusion that she was the best in the world.In psychiatry, delusion is used to mean an unshakeable belief in something that isn’t true. They believe it because they have a mental disorder, such as schizophrenia.More generally, delusion can be used to mean an act of deluding, as in The crowd didn’t fall for the swindler’s attempts at delusion.Delusion can also refer to the state of being deluded, as in The emperor’s delusion was the work of the evil, scheming vizier.Delusion is similar to the words illusion and hallucination, which also describe false beliefs or experiences. An illusion is a false image that is a result of a distortion or manipulation of actual things. For example, makeup can create the illusion that a person is younger than they actually are.A hallucination is a false sensory experience that isn’t rooted in reality at all. On the other hand, a delusion is often somewhat based on reality but a person’s belief is inaccurate due to wrong information or their own hubris.Example: Despite his low test scores, Gerard strongly believed the delusion that he was the smartest kid in the class.