OBSESSION meaning : 1. something or someone that you think about all the time: 2. something or someone that you think…. Learn more. Obsession definition : the domination of one's thoughts or feelings by a persistent idea, image, desire, etc.. See examples of OBSESSION used in a sentence. Define obsession . obsession synonyms, obsession pronunciation, obsession translation, English dictionary definition of obsession . ) n. 1. A pattern of unwanted or intrusive thoughts or urges that recur persistently, often accompanied by symptoms of anxiety. 2. A compulsive, often...