fanaticism

noun

1 a study of fanaticism during the French Revolution:

zealotry, zeal, extremism, militancy, sectarianism, fundamentalism, bigotry, dogmatism, chauvinism, radicalism, immoderation.

▷antonyms moderation.

2 informal his love of James Dean verged on fanaticism:

obsessiveness, over-enthusiasm, addiction, fixation, madness, monomania, immoderation, passion, infatuation;

enthusiasm, dedication, devotion, single-mindedness;

informal fandom;

rare fervency, ardency, passionateness.

▷antonyms indifference.