'pro-ministerially' originates from Latin prefix 'pro-' and the adjective 'ministerial' (from Latin 'ministerialis' via 'minister'), where 'pro-' meant 'for' and 'minister' meant 'servant/attendant (later a government official)'.

'minister' came into English via Old French 'ministre' from Latin 'minister'; 'ministerial' developed to mean 'pertaining to a minister' in English; the prefix 'pro-' (meaning 'for') combined with 'ministerial' to form 'pro-ministerial', and the adverbial suffix '-ly' produced 'pro-ministerially'.

Initially 'minister' meant 'servant' and 'ministerial' pertained to service; over time 'ministerial' came to mean 'of or relating to a government minister', and 'pro-ministerially' came to mean 'in support of ministers or ministerial authority'.