'nonconfederative' originates from the English negative prefix 'non' (ultimately from Latin 'non', meaning 'not') combined with 'confederative', which derives from Latin 'confoederare'/'confoederatus', where 'con-' meant 'together' and 'foedus' (from 'foederare') meant 'treaty' or 'league'.

'confederative' evolved from Old French 'confédératif' (from Latin 'confoederatus'), passed into Middle and Early Modern English as 'confederate'/'confederative', and 'nonconfederative' was formed in Modern English by prefixing 'non-' to create a negative adjective.

Initially the root 'confederate' meant 'joined by treaty' or 'bound in league'; 'nonconfederative' is a straightforward negational formation that came to mean 'not joining or forming such alliances' and has retained that negative sense.