delusion

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noun de·lu·sion \ di-ˈlü-zhən , dē- \

Definition of delusion

1 :the act of tricking or deceiving someone :the state of being deluded

… accused the Bohemian of having practised the most abominable arts of delusion among the younger brethren.
—Walter Scott

2 a :something that is falsely or delusively believed or propagated

under the delusion that they will finish on schedule

delusions of grandeur

b psychology :a persistent false psychotic belief regarding the self or persons or objects outside the self that is maintained despite indisputable evidence to the contrary

the delusion that someone was out to hurt him

; also :the abnormal state marked by such beliefs

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delusional

play \-ˈlüzh-nəl, -ˈlü-zhə-nᵊl\ adjective

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delusionary

play \-zhə-ˌner-ē\ adjective

See delusion defined for English-language learners

See delusion defined for kids

Examples of delusion in a Sentence

He has delusions about how much money he can make at that job.
He is living under the delusion that he is incapable of making mistakes.
She is under the delusion that we will finish on time.
As the illness progressed, his delusions took over and he had violent outbursts.

Recent Examples of delusion from the Web

There should be no delusion that even re-signing their best players will get the Raptors anywhere closer to the Cavs’ high-water mark, but there are worse outcomes than keeping a solid (if ill-fated) footing in the East’s competitive hierarchy.

— rob mahoney, SI.com, "Grades: Serge Ibaka Deal Should Help Raptors Make Ends Meet," 2 July 2017
The idea that porn prevented him from killing women was a self-serving delusion that justified his impulse to write and draw portrayals of torture.

— erin blakemore, Longreads, "Unknowable Dads: A Father’s Day Reading List," 19 June 2017
Andueza isn’t under any delusions that the new federal funds will solve all of Idaho’s opioid problems.

— john sowell, idahostatesman, "Has the opioid epidemic reached Idaho? Not like what’s seen back East," 16 June 2017
A classic example of one who fails to heed his own advice, Kohl’s defeat in 1998 and his tumble in the public’s esteem were seen by many as the results of seeking to hold power too long and suffering delusions of being above the law.

— carol j. williams, The Seattle Times, "Helmut Kohl, Germany’s ‘chancellor of unity’ who was marred by scandal, dies at 87," 16 June 2017
In modern times, just as further back in history, madness is a slippery concept, hard to pin down unless there are obvious signs of delusion, derangement, paranoia, or actual physical aggression.

— chicagotribune.com, "The Madness of King Donald," 14 June 2017
Colbert solved it by dialing the parody levels up to 11, making his Daily Show character a cable news pseudo-expert with godlike delusions of grandeur.

— david sims, The Atlantic, "Is Jordan Klepper the Future of Comedy Central?," 12 June 2017
That drug, Nuplacid, can be used for the treatment of hallucinations and delusions sometimes seen in people with Parkinson’s disease.

— dr. claes wahlestedt, miamiherald, "In treating mental illness, drugs are critical. Yet few are in the pipeline.," 6 June 2017
And mind control, fake broadcasts, memory police, and mass delusion in The Lie of the Land all nod pleasingly at George Orwell's 1984.

— kelly fiveash, Ars Technica, "The Lie of the Land," 4 June 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'delusion.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of delusion

Middle English, from Late Latin delusion-, delusio, from deludere — see delude

NEW! Time Traveler

First Known Use: 15th century

See Words from the same year

delusion Synonyms

Synonyms

chimera, conceit, daydream, fantasy, dream, fancy, figment, hallucination, illusion, nonentity, phantasm (also fantasm), pipe dream, unreality, vision

Antonyms

truth, verity

Related Words

ignis fatuus, mirage, will-o'-the-wisp; brainchild, idea; concoction, fable, fabrication, fiction, invention; envisaging, imaging, visualization; cloud-cuckoo-land, cloudland, Shangri-la, utopia; daymare, nightmare

Near Antonyms

actuality, fact, reality

Synonym Discussion of delusion

delusion, illusion, hallucination, mirage mean something that is believed to be true or real but that is actually false or unreal. delusion implies an inability to distinguish between what is real and what only seems to be real, often as the result of a disordered state of mind.

- delusions of persecution

illusion implies a false ascribing of reality based on what one sees or imagines.

- an illusion of safety

hallucination implies impressions that are the product of disordered senses, as because of mental illness or drugs.

- suffered from terrifying hallucinations

mirage in its extended sense applies to an illusory vision, dream, hope, or aim.

- claimed a balanced budget is a mirage

Other Psychology Terms

fetish, hypochondria, intelligence, mania, narcissism, neurosis, pathological, psychosis, schadenfreude, subliminal

DELUSION Defined for English Language Learners

delusion

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noun

Definition of delusion for English Language Learners

: a belief that is not true : a false idea
: a false idea or belief that is caused by mental illness

DELUSION Defined for Kids

delusion

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noun de·lu·sion \ di-ˈlü-zhən \

Definition of delusion for Students

:a false belief that continues in spite of the facts

“You might be laboring under the delusion that the entire … world is impressed with you …”
—J. K. Rowling, Goblet of Fire

Medical Dictionary

delusion

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noun de·lu·sion \ di-ˈlü-zhən \

medical Definition of delusion

1 a :the act of deluding :the state of being deluded

b :an abnormal mental state characterized by the occurrence of psychotic delusions

2 :a false belief regarding the self or persons or objects outside the self that persists despite the facts and occurs in some psychotic states — compare hallucination 1, illusion 2a