What is hallucination in LLMs?

Answer

Hallucination is when a language model produces text that sounds confident and plausible but is factually wrong or unsupported by its sources. It happens because the model generates statistically likely text rather than retrieving verified facts, so gaps in knowledge are filled with fabrication. Mitigations include grounding answers with retrieval (RAG), asking for citations, lowering temperature, and validating outputs against trusted data before acting on them.