hallucination means When an AI model confidently generates false information — citing non-existent sources, inventing people, fabricating quotes. It's mostly used in casual online conversation. It's casual and generally safe with friends and online. It's standard online vocabulary; nothing inherently concerning about hearing it.
hallucination
When an AI model confidently generates false information — citing non-existent sources, inventing people, fabricating quotes.
/həˌluːsɪˈneɪʃən/Documented since 2010s2010sGen AlphamainstreamCurrent6.8K viewsLast reviewed Jun 29, 2026＋ Add a definition
Seen in the wild
3 citations · last seen May 2026
Etymology timeline
Born ~2018 · 1 year of recorded useSeen in the wild
BlueskyMay 2026
Tbh, so many of the people in it felt interchangeable like something out of a Brett Easton Ellis novel. They all parrot the same ideology so it just reads like a collective hallucination.
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BlueskyMay 2026
Only the very slight problem that everything an LLM outputs is an "hallucination", just some hallucinations happen to correspond to our sense of reality.
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BlueskyMay 2026
Calling it "hallucination" was just marketing bullshit to get people to think of chatbots as sentient beings. Now that the term has become widely used, the tech bros want us t believe you can instruct the model to no…
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Wikipedia: Hallucination
A mild form of hallucination is known as a disturbance, and can occur in most of the senses above.
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Wikipedia: Hallucination
A hallucination is a perception in the absence of an external context stimulus that has the compelling sense of reality.
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Definitions
Global
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#1·Apr 23, 2026GlobalWork-OK
When an AI model confidently generates false information — citing non-existent sources, inventing people, fabricating quotes. A core limitation of LLMs.
Origin: Tech / AI / developer industry term.
For parents
hallucination means When an AI model confidently generates false information — citing non-existent sources, inventing people, fabricating quotes. It's mostly used in casual online conversation. It's casual and generally safe with friends and online. It's standard online vocabulary; nothing inherently concerning about hearing it.
For ESL learners
"hallucination" is slang. It means: When an AI model confidently generates false information — citing non-existent sources, inventing people, fabricating quotes. Register: casual. Use it in: casual conversation and online posts. Avoid in: formal writing and professional emails.
Cluster: technology
Heard in the wild
“Tbh, so many of the people in it felt interchangeable like something out of a Brett Easton Ellis novel. They all parrot the same ideology so it just reads like a collective hallucination.”
— Bluesky· May 2026“Only the very slight problem that everything an LLM outputs is an "hallucination", just some hallucinations happen to correspond to our sense of reality.”
— Bluesky· May 2026“Calling it "hallucination" was just marketing bullshit to get people to think of chatbots as sentient beings. Now that the term has become widely used, the tech bros want us t believe you can instruct the model to not "hallucinate". It is so silly.”
— Bluesky· May 2026“A mild form of hallucination is known as a disturbance, and can occur in most of the senses above.”
“A hallucination is a perception in the absence of an external context stimulus that has the compelling sense of reality.”
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Comments (1)
Refers specifically to an AI model stating false information with unwarranted confidence — inventing sources, people, or quotes — not just any AI mistake or low-quality output. It names the confidence-without-accuracy problem, not a general synonym for 'wrong.' — Slangora Editors
Global
+512100%
#2·Apr 24, 2026GlobalNeutral
Infamous hallucination examples: non-existent Supreme Court cases (2023 Mata v. Avianca), invented academic citations, a Google AI recommending "glue on pizza" (2024), and every time ChatGPT confidently misremembers Taylor Swift lyrics.
"The chatbot told me Shakespeare wrote Les Mis. Peak hallucination."
Origin: Tech / AI / developer industry term.
Cluster: technology
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#3·Apr 24, 2026GlobalWork-OK
Contested technical framing: some AI researchers argue "hallucination" anthropomorphizes the model. Alternatives like "confabulation," "fabrication," or simply "error" are used in stricter papers.
Origin: Tech / AI / developer industry term.
Cluster: technology
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#4·Apr 24, 2026GlobalWork-OK
Mitigations are well-understood in principle — RAG grounding, citation enforcement, verification chains, refusal-when-uncertain training. In practice, zero of these fully eliminate hallucinations in open-ended tasks. The error rate can be reduced, not removed.
"We cut hallucination rates by 70% with grounded generation. The other 30% is just… the model."
Origin: Tech / AI / developer industry term.
Cluster: technology
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For specific readers
Why is this section here?
Slang is read by different audiences for very different reasons. The For parents view re-explains the term in plain, non-judgemental language so a caregiver can understand what their child means without needing the surrounding subculture. The For English learners view focuses on register (when it's safe to use), formal alternatives, and common mistakes — what a textbook won't teach you.
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⚡About Tech, Dev & AI slang
The vocabulary of software engineers, AI researchers, and anyone living in a terminal or on GitHub — from LLM to MCP, CORS to vibe coding, agentic to enshittification.
See all Tech, Dev & AI slang on Slangora.
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Other words near "hallucination" (H)
Hallmark momenthall monitorhall of residencehall passhallshallucinate uphallucination archallucination checkhallucination codedhallucination corehallucination energyhallucination mode
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Semantically related
- hallucinate up83%
When an AI fabricates plausible-sounding but false information in a confident, high-quality register. Verb form of "hallucination." "It hallucinated up a library that doesn't exist and six methods that don't compile." Every working LLM engineer has a hallucinate-up horror story.
- hallucination mode77%
Hallucination mode is when someone — or something — enters a state of confidently generating nonsense with zero apparent awareness that any of it is wrong. Originally describing the behavioral pattern of AI models that produce fluent, plausible-sounding falsehoods, hallucination mode has slipped into human slang to describe anyone running their mouth (or keyboard) with high confidence and low accuracy. It's that person in the meeting who is clearly winging it with authoritative energy, or the friend who just spent twenty minutes explaining something they clearly half-read once. The mode is the commitment to the bit, factual accuracy optional.
- grounding72%
Tying an AI's output to verified external facts (documents, databases, search results) to reduce hallucination. RAG is the most common technique.