The story
From Epicurean + -ism. As a pejorative synonym of atheism, both from the philosophy's rejection of deontological morality and from Epicurus's specific belief that the Greek gods—if they did exist—did not concern themselves at all with mankind, its actions, or any system of reward or punishment for them. Doublet of epicurism.
Etymology from Wiktionary, CC BY-SA 4.0.