ob·ses·sive-com·pul·sive disorder (?b-s?s??v-k?m-p?l?s?v, ?b-)n. Abbr. OCD A psychiatric disorder characterized by the presence of either obsessions (repeated, unwanted, often distressing thoughts), or compulsions (the feeling of being driven to repeatedly perform certain behaviors or mental activities), or both, with the symptoms being severe enough to impair normal functioning.ob·ses?sive-com·pul?sive adj.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.obses?sive-compul?sive adj. 1. of, pertaining to, or characterized by the persistent intrusion of unwanted thoughts accompanied by ritualistic actions, regarded as a form of neurosis. n. 2. a person with obsessive-compulsive characteristics. [1925?30] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.