'post-reform' is a compound formed from the Latin prefix 'post' (from Latin 'post', meaning 'after') and the noun 'reform' (from Latin 'reformare' via Old French 'reformer').

'post' entered English as a prefix from Latin 'post'. 'Reform' came into English from Old French 'reformer' and Medieval Latin 'reformare', and the compound 'post-reform' was formed in modern English by combining the prefix and the noun.

Initially the elements meant 'after' (post) and 'to form again' (reform/ reformare); over time the compound came to mean simply 'after a reform' or 'relating to the period after a reform'.