'antipapalism' originates from Greek and Latin elements: the prefix 'anti-' from Greek 'anti-' meaning 'against', combined with Latin 'papalis' (from 'papa' meaning 'pope') via English 'papal', and the suffix '-ism' from Greek '-ismos' via Latin '-ismus' meaning 'doctrine or practice'.

'antipapalism' formed in English by attaching the suffix '-ism' to 'antipapal' (itself 'anti-' + 'papal'); 'papal' comes from Latin 'papa' > Late Latin 'papalis' > Old French/Medieval Latin forms before becoming English 'papal'.

Initially it simply signified 'opposition to the pope' and over time has retained that core meaning while being used in broader contexts to denote hostility to papal authority or influence.