Paranoid describes someone who feels, often without good reason, that other people are watching them, talking about them, or trying to harm them. In everyday talk, people use it loosely for ordinary worry or suspicion — 'don't be so paranoid, nobody's judging you.' In medicine and psychology, it's a more serious word: a real mental health condition where a person has strong, fixed beliefs that others mean them harm, even when there's no evidence at all. The casual, everyday use is much weaker than the medical one, so context matters a lot.

疑神疑鬼、多疑（醫學上指「妄想型」）