An AI answer that sounds right but is actually false or unproven.
Hallucination is like a friend giving directions with full confidence. Then you find the pizza place is a pond.
It can fill blanks when writing. It can trap you during research. Check important facts before you trust it.
LLM
An LLM predicts likely words, so it can hallucinate.
Prompt
A clear Prompt leaves less empty space for hallucination.
RAG
RAG gives the AI sources it can check before it answers.
Alignment
Alignment trains the AI to avoid shaky answers.