'antipapist' originates from modern English, specifically formed from the prefix 'anti-' (from Greek 'anti-' meaning 'against') and the noun 'papist' (ultimately from Latin 'papa'/'papista'), where 'anti-' meant 'against' and 'papa' meant 'father' (used for the Pope).

'papist' came into English from Old French 'papiste' (from Late Latin 'papista'), meaning a follower of the Pope; English speakers later combined the prefix 'anti-' with 'papist' to form 'antipapist' (used in early modern and modern English to denote opposition to the papacy).

Initially it specifically denoted someone 'against the Pope' or 'against papal authority,' and this core meaning has largely remained unchanged, though its use is now chiefly historical or specialized.