par ‧ a ‧ noid /ˈpærənɔɪd/ BrE AmE adjective
1 . believing unreasonably that you cannot trust other people, or that they are trying to harm you or have a bad opinion of you
be/become/get paranoid
Malcolm got really paranoid, deciding that there was a conspiracy out to get him.
paranoid about
He has always been paranoid about his personal security.
2 . medical suffering from a mental illness that makes you believe that other people are trying to harm you:
a patient suffering from paranoid schizophrenia