'antimoralist' originates from Modern English, formed by the prefix 'anti-' (from Greek 'antí' meaning 'against') combined with 'moralist' (from French 'moraliste' and Latin 'moralis', ultimately from Latin 'mos/mores' meaning 'customs' or 'morals').

'moralist' came into English via French 'moraliste' from Late Latin 'moralis' (relating to 'mos/mores'), while the prefix 'anti-' comes from Greek 'antí'. These elements were combined in Modern English to produce 'antimoralist'.

Initially it meant 'one who is against moralism or moralizers', and it has retained that sense of opposition to conventional moralism in contemporary usage.