幻觉 (huàn jué): Hallucination / Illusion (Noun) — Meaning & Stroke Order

Are you sure you heard a strange sound just now, or was that just your hallucination?

He had hallucinations because he was too tired.

Chronic sleep deprivation can indeed easily cause people to have various vivid hallucinations.

In the desert, mirages are a common natural illusion.