'antipapism' originates from Greek and Late Latin elements: the prefix 'anti-' from Greek 'anti' where it meant 'against', and 'papism' ultimately from Late Latin 'papa' (via Old French 'papisme'), where 'papa' meant 'pope'.

'antipapism' was formed by combining the Greek prefix 'anti-' with 'papism' (from Middle English/Old French 'papisme', from Late Latin 'papa'), and eventually became the modern English word 'antipapism'.

Initially it referred specifically to opposition to the Pope or papal authority; over time it has retained that core meaning and is chiefly used in historical and theological contexts.