'anti-confederationism' originates from English compounding of three elements: the prefix 'anti-' (from Greek 'anti', where 'anti-' meant 'against'), the noun 'confederation' (from Medieval Latin 'confœderatio'/'confoederatio' meaning 'a league, alliance'), and the suffix '-ism' (from Greek '-ismos' via Latin/French, forming nouns that denote doctrines or movements).

'confederation' developed from Latin 'confoederatio' (or Medieval Latin 'confederatio'), passed into Old French (e.g. 'confederacion') and Middle English as 'confederacioun' before becoming modern English 'confederation'; combined with the productive English prefix 'anti-' and the noun-forming suffix '-ism' to yield 'anti-confederationism'.

Initially the elements meant 'against' + 'a league/union' + 'doctrine/movement'; over time the compound came to denote specifically a political stance or ideology opposing the creation or expansion of a confederation.