An Anathema

1. (ecclesiastical, historical) A ban or curse pronounced with religious solemnity by ecclesiastical authority, often accompanied by excommunication; something denounced as accursed. [from early 17th c.] Synonyms: ban, curse Anathema - Wikipedia
2. (by extension) Something which is vehemently disliked by somebody. Synonym: bête noire
3. (literary) An imprecation; a curse; a malediction.
4. (ecclesiastical) Any person or thing anathematized, or cursed by ecclesiastical authority to unending punishment. [from 1520s]