'antipapistical' originates from Modern English, specifically formed from the prefix 'anti-' meaning 'against' and the adjective 'papistical' (relating to the pope).

'papistical' is derived from 'papist' (from early modern English), which in turn comes from Medieval Latin 'pāpista' and Latin 'papa' meaning 'pope'; 'antipapistical' is a later compound created in English by adding 'anti-' to 'papistical'.

Initially it meant 'against the pope or papal authority,' and this central sense has been retained in the modern usage.