n. [ NL., fr. Gr. para`noia. ] 1. (Med.) A chronic form of insanity characterized by very gradual impairment of the intellect, systematized delusion, and usually by delusions of persecution or mandatory delusions producing homicidal tendency. In its mild form paranoia may consist in the well-marked crotchetiness exhibited in persons commonly called “cranks.” Paranoiacs usually show evidences of bodily and nervous degeneration, and many have hallucinations, esp. of sight and hearing. [ Webster 1913 Suppl. ]

2. Unwarranted suspicion of the motives of others; -- used colloquially in a non-technical sense. [ Colloq. ] [ PJC ]

a. (Med.) Of or pertaining to paranoia; affected with, or characteristic of, paranoia; paranoid. [ Webster 1913 Suppl. +PJC ]

n. A person affected with paranoia. [ Webster 1913 Suppl. ]

a. 1. (Med.) Affected with paranoia; as, a paranoid schizophrenic.
Syn. -- paranoiac. [ PJC ]

2. Suffering from delusions of being persecuted by the conspiratorial actions of others; having an unwarranted suspicion of the motives of others; -- used loosely in a negative sense, not as a medical term; as, just because you're paranoid doesn't mean they are not out to get you. [ Colloq. ] [ PJC ]