From King Dictionary of Contemporary Englishparanoiapar‧a‧noi‧a /ˌpærəˈnɔɪə/ noun [uncountable] 1 WORRIEDan unreasonable belief that you cannot trust other people, or that they are trying to harm you or have a bad opinion of you2 medicalMP a mental illness that makes someone believe that they are very important and that people hate them and are trying to harm them
Examples from the Corpus
paranoiaWas it paranoia or could she really feel some one closing in on her?If she mentioned paranoia, Buzz would insist that Elinor was the victim of a lot of quacks.Douglas also developed some mild paranoia that, in a president, might have had far more serious consequences.He had looked and sounded alone, and inadvertently given the impression of paranoia.She saved her curses until she could shout them into the night - then swallowed them anyway out of paranoia.Others may under-report due to dishonesty, forgetfulness or paranoia.It seemed possible that Soviet paranoia could spark a war at any time.He has never recovered from the paranoia of the Nixon years, and his reclusiveness is legendary.
Origin paranoia (1800-1900) Greek mental illness, from para- (PARA-) + nous mind