anathema

Something that one absolutely and positively cannot stand is anathema. Garlic is anathema to vampires (ditto for stakes and daylight). So is kryptonite to Superman or a silver bullet to a werewolf.

Originally the term anathema comes from the Catholic practice of denouncing a particular individual or idea that was antithetical to the Catholic Church. If done to a person, it excommunicated them, meaning they could no longer partake in the church's sacraments (with presumably pretty poor consequences for the soul.) That's a lot worse than kryptonite.

Definitions of anathema
1

n a formal ecclesiastical curse accompanied by excommunication

Type of:
condemnation, curse, execration
an appeal to some supernatural power to inflict evil on someone or some group

n a detested person

“he is an anathema to me”
Synonyms:
bete noire
Type of:
disagreeable person, unpleasant person
a person who is not pleasant or agreeable

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