idée fixe

something about which one is constantly thinking or concerned <had this bizarre idée fixe that people were spying on her with electromagnetic waves> Synonyms fetish (also fetich), fixation, mania, obsession, preoccupation, prepossessionRelated Words monomania; complex, hang-up, problem, trip; appetite, cacoëthes, compulsion, craving, desire, drive, enthusiasm, fascination, hankering, hunger, infatuation, itch, longing, lust, passion, pining, thirst, urge, yearning, yen; idiosyncrasy, quirk; bent, disposition, inclination, leaning, partiality, penchant, predilection, predisposition, proclivity, propensity, tendencyNear Antonyms apathy, disinterestedness, disregard, indifference, insouciance, nonchalance, unconcern, unconcernedness