noun, masculine/fa.na.tism/plural: fanatismes
fanaticism (the characteristic or practice of being a fanatic)
“1864, Rudolf Charles, Preface to Testament by Jean Meslier, page 8” — Our common idea, consistent with that of Mr Junghuhn, took shape by our different little essays, all openly attacking the fanaticism and lies of the Christian church, all aiming to propagate the love of truth, and to break the yoke of blind faith.