'anti-papalism' is formed from the Greek prefix 'anti-' meaning 'against', the adjective 'papal' (from Latin 'papa' meaning 'father' used of the pope), and the suffix '-ism' (from Greek '-ismos' via Latin/Old French) used to denote doctrines, systems, or movements.

'papa' (Medieval Latin) gave rise to 'papal' in English (relating to the pope); the noun-forming suffix '-ism' produced 'papalism' (support or system relating to papal authority), and the addition of the prefix 'anti-' produced the modern compound 'anti-papalism'.

Originally 'papa' meant 'father'; over time 'papal' came to mean 'relating to the pope', and 'anti-papalism' specifically came to mean 'opposition to papal authority or influence'.