Originally Posted by crockett

ob·ses·sion
əbˈseSHən/
noun
the state of being obsessed with someone or something.
"she cared for him with a devotion bordering on obsession"
an idea or thought that continually preoccupies or intrudes on a person's mind.
plural noun: obsessions
"he was in the grip of an obsession he was powerless to resist"
synonyms: fixation, ruling/consuming passion, passion, mania, idée fixe, compulsion, preoccupation, infatuation, addiction, fetish, craze, hobbyhorse; M