One word substitute is Blasphemy.Atheism: disbelief or lack of belief in the existence of God or gods.Nihilism: the rejection of all religious and moral principles, in the belief that life is meaningless.Blasphemy: the action or offence of speaking sacrilegiously about God or sacred things; profane talk.Agnosticism: the view that the existence of God, of the divine or the supernatural is unknown or unknowable.