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
Derived Forms
Inflected Forms
Participles
Conjugated Forms
Present
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hallucinatesimple
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hallucinatessimple
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have hallucinatedperfect
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has hallucinatedperfect
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am hallucinatingprogressive
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are hallucinatingprogressive
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is hallucinatingprogressive
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have been hallucinatingperfect progressive
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has been hallucinatingperfect progressive
Past
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hallucinatedsimple
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had hallucinatedperfect
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was hallucinatingprogressive
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were hallucinatingprogressive
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had been hallucinatingperfect progressive
Future
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.
See Examples For:
This training also makes clear that AI tools can be sycophantic and hallucinate, he adds.
From BBC ● Jun. 1, 2026
I set up this new session by harnessing the same sycophantic, people-pleasing tendencies that can make AI hallucinate in the first place.
From The Wall Street Journal ● May 19, 2026
But new research suggests there may be a more concerning issue emerging: humans can begin to "hallucinate with AI."
From Science Daily ● May 11, 2026
AI tools are known to hallucinate, or make up information.
From Los Angeles Times ● Apr. 14, 2026
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
If an agent hallucinates, Arcade can catch the error and correct it, allowing the workflow to continue, he said.
From The Wall Street Journal ● Jun. 15, 2026
"This means that visual information about things happening in the outside world becomes less accessible to our consciousness. To fill this gap in the puzzle, our brain inserts fragments from memory -- it hallucinates."
From Science Daily ● Feb. 15, 2026
What good is AI that analyzes financial data if it hallucinates numbers?
From MarketWatch ● Nov. 3, 2025
The puppeteer even hallucinates seeing Eric standing next to him, wisecracking and poking holes in his ego - because "puppets say the things we can't".
From BBC ● May 26, 2024
Sometimes Enrique hallucinates that someone is chasing him.
From "Enrique's Journey" by Sonia Nazario
Last year, a Los Angeles attorney was fined for submitting a filing full of legal citations that were hallucinated by ChatGPT.
From Los Angeles Times ● Mar. 18, 2026
And then ‘oh, no, it hallucinated and deleted all my emails’ or worse,” said CrowdStrike Chief Technology Officer Elia Zaitsev.
From The Wall Street Journal ● Mar. 16, 2026
One out of every five answers "contained major accuracy issues, including hallucinated details and outdated information."
From Barron's ● Oct. 21, 2025
Earlier this year, Apple suspended its Apple Intelligence news summary tool in the UK after it hallucinated false headlines and presented them as real news.
From BBC ● Mar. 20, 2025
“The Dauntless serum gives hallucinated realities, Candor’s gives the truth, Amity’s gives peace, Erudite’s gives death—” At this, Tris visibly shudders, but Johanna continues as if it didn’t happen.
From "Allegiant" by Veronica Roth
When generative AI systems give incorrect answers, people often describe the problem as AI "hallucinating at us," meaning the technology produces false information that users may mistakenly believe.
From Science Daily ● May 11, 2026
Newer language models are known for being overly encouraging or sycophantic towards users, as well as for hallucinating - meaning they make things up.
From BBC ● Apr. 29, 2026
"This risk of a model making errors or hallucinating cannot be fully avoided in any technical way," said Munich Re's head of AI insurance, Michael von Gablenz.
From Barron's ● Mar. 15, 2026
A hallucinating encyclopedia may not be exactly what you’re looking for when you’re doing research, but that’s what writer Stephen Harrison found when he dug into Elon Musk’s new A.I.-powered Grokipedia.
From Slate ● Nov. 17, 2025
For a moment I think I’m hallucinating, because she walks out.
From "The Girl on the Train" by Paula Hawkins
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.
