illusion

American  

[ih-loo-zhuhn] / ɪˈlu ʒən /

noun

• illusions
  plural

1. something that deceives by producing a false or misleading impression of reality.

   Synonyms:

   chimera, fantasy, aberration

2. the state or condition of being deceived; misapprehension.

3. an instance of being deceived.

4. Psychology. a perception, as of visual stimuli optical illusion, that represents what is perceived in a way different from the way it is in reality.

5. a very thin, delicate tulle of silk or nylon having a cobwebbed appearance, for trimmings, veilings, and the like.

6. Obsolete. the act of deceiving; deception; delusion.

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illusion British  

/ ɪˈluːʒən /

noun

1. a false appearance or deceptive impression of reality

   the mirror gives an illusion of depth

2. a false or misleading perception or belief; delusion

   he has the illusion that he is really clever

3. psychol a perception that is not true to reality, having been altered subjectively in some way in the mind of the perceiver See also hallucination

4. a very fine gauze or tulle used for trimmings, veils, etc

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Synonym Usage

illusion, hallucination, delusion refer to false perceptions or ideas. An illusion is a false mental image produced by misinterpretation of things that actually exist: A mirage is an illusion produced by reflection of light against the sky. A hallucination is a perception of a thing or quality that has no physical counterpart: Under the influence of LSD, Terry had hallucinations that the living-room floor was rippling. A delusion is a persistent false belief: A paranoiac has delusions of persecution.

Other Word Forms

Derived Forms

• illusionary
  adjective
• illusioned
  adjective

Inflected Forms

Nouns

• illusions
  plural

Etymology

Origin of illusion

First recorded in 1300–50; Middle English from Latin illūsiōn- (stem of illūsiō ) “irony, mocking,” equivalent to illūs(us), past participle of illūdere “to mock, ridicule” ( il- il- ¹ + lūd- play ( see ludicrous) + -tus past participle suffix) + -iōn- -ion

Explanation

An illusion is something that isn't real. It may look real, but it's actually fake — just a crafty construction or fantasy. Like the old rabbit-out-of-the-hat trick practiced by magicians around the globe. An illusion is an act of deception. Some optical illusions are pretty cool to watch, but an illusion can also point to an erroneous belief or false perception of reality, which is where you start getting into hallucination territory — seeing things that aren't there. You can give the illusion that you’re fascinated by your professor’s lecture by chewing on your pencil, furrowing your brow, and making sure to nod enthusiastically every so often.

Example Sentences

See Examples For:

illusion illusions

At the same time Nunez has said he is under no illusion that some French politicians will continue to spread views similar to hers.

From Barron's ● Jul. 31, 2026

Even here, though, historians have noted that the Soviet Union’s near-simultaneous invasion of Manchuria—which dispelled Japan’s illusion that Moscow might stay neutral in the war—also had an impact on the emperor’s calculations.

From Slate ● Jul. 30, 2026

The final twist is one of the bleakest endings in postwar fiction, precisely because it exposes survival itself as a kind of illusion.

From The Wall Street Journal ● Jul. 22, 2026

"I don't think anybody is under any illusion about the financial challenges we're all facing these days - there are requirements to cut back and to freeze funding," he warned.

From BBC ● Jul. 20, 2026

They don’t know that the boarded-up door is only an illusion hiding a steel door with ancient markings on it.

From "The Manifestor Prophecy" by Angie Thomas

Still, Raines, 79, has no illusions about the challenges the city faces.

From Los Angeles Times ● Aug. 9, 2026

Agyarko is under no illusions as to the magnitude of the task that stands in front of him this weekend.

From BBC ● Jul. 22, 2026

"He would never do that, let's not have any illusions," said Tikhanovskaya, who recently returned from a trip to Kyiv.

From Barron's ● Jun. 26, 2026

Investigating four centuries of British and American data, Mr. Goodspeed concludes that the apparent business cycles that economists have spent careers documenting are “apophanies” rather than epiphanies: illusions of pattern imposed on noise.

From The Wall Street Journal ● Jun. 5, 2026

The case Madison had tried to make for the Potomac was simultaneously crafty and driven by romantic illusions about its prowess that were shared by Jefferson, Washington, and most members of the Virginia dynasty.

From "Founding Brothers: The Revolutionary Generation" by Joseph J. Ellis

Related Words

• confusion
• deception
• delusion
• fantasy
• hallucination
• image
• misconception
• myth
• pipe dream
• semblance