Obsession

 b·ses·sion [uhb-sesh-uhn]

 -noun

• the domination of one's thoughts or feelings by a persistent idea, image, desire, etc.
• the idea, image, desire, feeling, etc., itself.
• the state of being obsessed.
• the act of obsessing. 

[Origin: 1505–15;  L obsessiōn- (s. of obsessiō) blockade, siege, equiv. to obsess(us) (see obsess) + -iōn- -ion]

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