hallucinate
Americanverb (used without object)
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to see or hear things that do not exist outside the mind; have hallucinations.
People who ingested this fungus often hallucinated, seeing colored lights or hearing voices.
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Computers, Digital Technology. (of a machine learning program) to produce false information contrary to the intent of the user and present it as if true and factual.
verb (used with object)
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to see or hear (things that do not exist outside the mind); have hallucinations about.
In dramatic moments, the character hallucinates a very funny animated bear.
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Archaic. to affect with hallucinations.
verb
Other Word Forms
- hallucinator noun
- nonhallucinated adjective
- unhallucinated adjective
- unhallucinating adjective
Etymology
Origin of hallucinate
First recorded in 1595–1605; from Latin hallūcinātus “wandered mentally” past participle of hallūcinārī, variant of (h)ālūcinārī “to dream, talk idly, wander mentally”
Explanation
To hallucinate is to see or hear something that's not really there. If you hallucinate, it's a bit like dreaming while being awake. When someone hallucinates, what they're perceiving seems very real and vivid, although it's not. Many different things can cause a person to hallucinate, including drugs, mental illness, damage to the brain, and even lack of adequate sleep. Some people hallucinate regularly, if mildly, just as they're falling asleep at night. The original meaning of hallucinate was "deceive," from the Latin hallucinatus, "wander in the mind."
Vocabulary lists containing hallucinate
The Marvels
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Ungifted
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The Legend of Auntie Po
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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.
Since AI tools are known to hallucinate, or make up information, workers should demonstrate that they check the information they’re given and don’t always rely on the same offerings.
From MarketWatch • Apr. 11, 2026
Generative artificial intelligence is also still prone to error and may "hallucinate" elements that were not in the original image, Kanoulas added.
From Barron's • Mar. 10, 2026
Especially as someone who hasn’t been back in a long time—when I see these images, they almost make me hallucinate.
From Slate • Mar. 3, 2026
Like ChatGPT, these AI-powered assistants sometimes hallucinate, too.
From The Wall Street Journal • Oct. 3, 2025
Perhaps it had escaped and was hiding in one of the dark corners of the room, or maybe Joseph’s fever was causing him to hallucinate.
From "The Marvels" by Brian Selznick
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
