1. Psychiatry. a mental disorder characterized by systematized delusions and the projection of personal conflicts, which are ascribed to the supposed hostility of others, sometimes progressing to disturbances of consciousness and aggressive acts believed to be performed in self-defense or as a mission.
  2. baseless or excessive suspicion of the motives of others.
Also par·a·noe·a [par-uh-nee-uh] /ˌpær əˈni ə/.

Origin of paranoia

1805–15; < New Latin < Greek paránoia madness. See para-1, nous, -ia Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for paranoea


  1. a form of schizophrenia characterized by a slowly progressive deterioration of the personality, involving delusions and often hallucinations
  2. a mental disorder characterized by any of several types of delusions, in which the personality otherwise remains relatively intact
  3. informal intense fear or suspicion, esp when unfounded
Derived Formsparanoiac (ˌpærəˈnɔɪɪk) or paranoic (ˌpærəˈnəʊɪk), adjective, noun

Word Origin for paranoia

C19: via New Latin from Greek: frenzy, from paranoos distraught, from para- 1 + noos mind
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for paranoea



"mental disorder characterized by systematized delusions," 1848 (earlier paranoea 1811), from Greek paranoia "mental derangement, madness," from paranoos "mentally ill, insane," from para- "beside, beyond" (see para- (1)) + noos "mind."

FOR several years frequent descriptions have been given in the foreign journals, especially German and Italian, of the forms of insanity designated by the names Paranoia, Verrücktkeit, and Wahnsinn. ["Paranoia -- Systematized Delusions and Mental Degenerations," J. Séglas (transl. William Noyes), 1888]
Online Etymology Dictionary, © 2010 Douglas Harper

paranoea in Medicine


  1. A psychotic disorder characterized by systematized delusions, especially of persecution or grandeur, in the absence of other personality disorders.
  2. Extreme, irrational distrust of others.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

paranoea in Culture



A form of psychosis marked by delusions of persecution and of grandeur. One who suffers from paranoia is paranoid.


In popular terminology, a “paranoid” personality is characterized by suspicion and distrust of others; a tendency to look for hidden meaning behind other people's actions; argumentativeness; complaining; low tolerance for criticism; and a constant display of one's own talents, accomplishments, independence, and rationality.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.