noun

the quality of being fanatical.

the dangers of religious fanaticism

zealotry,zeal,extremism,militancy,sectarianism,fundamentalism,bigotry,dogmatism,chauvinism,radicalism,immoderation,obsessiveness,over-enthusiasm,addiction,fixation,madness,monomania,passion,infatuation,enthusiasm,dedication,devotion,single-mindedness,fandom,fervency,ardency,passionateness