What is Hallucination?

Hallucination: an AI term, explained in plain English.

In one line

When an AI model states something false or made up as if it were true, such as a fake fact, quote or source.

AI Reviewed by Keshav Aggarwal · Updated 5 Nov 2026

In simple words

Imagine asking a child about a book they never read. Instead of saying “I don’t know”, they make up a story that sounds right.

When an AI does that, we call it a hallucination.

The technical side

Language models generate the most likely next tokens, not checked facts, so they can produce fluent but wrong statements, invented citations or wrong numbers. Hallucinations are more likely on rare topics, recent events after the model’s training data, and exact figures.

Grounding answers in sources (RAG), asking the model to cite, and checking important claims by hand reduce the risk.

Hallucination kya hai?

Hallucination tab hota hai jab AI galat baat bhi poore bharose se bol deta hai, jaise nakli fact ya nakli source. Isliye AI ki zaroori baatein hamesha check karo.

Related terms

LLM (Large Language Model)AIAn AI model trained on huge amounts of text so it can read and write language, like the models behind ChatGPT, Claude and Gemini.

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