One with an obsessive interest in something, particularly (originally derogatory) an obsessive Japanese fan of anime or manga.
Word Origin
From Japanese オタク (otaku, “anime obsessive, geek”) originally used in reference to the 1982 Macross fandom, from the honorific form お宅 (otaku, “you”), from the honorific form 宅 (taku, “home”) ("your h...