Paranoia is thinking and feeling like you are being threatened in some way, even if there is no evidence, or very little evidence, that you are. Paranoid thoughts could also be exaggerated suspicions. For example, someone made a nasty comment about you once, and you believe that they are directing a hate campaign against you.
*Adapted or taken from “Overcoming Paranoid and Suspicious Thoughts: A self-help guide using cognitive behavioural techniques” (2016) by Daniel Freeman, Jason Freeman, Philippa Garety