'papistical' originates from Middle English and Early Modern English, ultimately from Late Latin 'papista' (via Old French 'papiste'), where 'papa' meant 'father' (used for the bishop of Rome, i.e. the pope) and the suffix '-ical' formed adjectives meaning 'relating to'.

'papistical' developed from the noun 'papist' (Middle English < Old French 'papiste' < Late Latin 'papista'), with the adjective-forming suffix '-ical' (from Latin '-icus') producing adjectives such as 'papistical' in Early Modern English.

Initially related simply to 'of or pertaining to a papist or the papacy', the word has often been used over time with a more explicitly supportive or sometimes pejorative sense of 'excessively or blindly supportive of papal authority'.