'non-puritanical' originates from English, specifically the prefix 'non-' + the adjective 'puritanical', where 'non-' meant 'not' and 'puritanical' is formed from 'Puritan' (a member of the Puritans) + the adjectival suffix '-ical'.

'puritanical' developed from the noun 'Puritan' (referring to the religious group 'Puritans' in 16th–17th century England), then took the suffix '-ical' to form 'puritanical'; later, the productive prefix 'non-' was attached to form 'non-puritanical' meaning 'not puritanical'.

Initially, 'puritanical' related directly to the Puritans and their strict moral standards; over time it generalized to describe strict or censorious moral attitudes, and 'non-puritanical' came to mean the opposite—lacking such strictness or censoriousness.