'antineutralism' originates from Modern English, specifically a compound of the prefix 'anti-' and the noun 'neutralism'; 'anti-' ultimately comes from Greek 'anti' (ἀντί), where 'anti-' meant 'against', and 'neutralism' derives from 'neutral' + '-ism' (with 'neutral' from Old French 'neutre' and Latin 'neuter').

'antineutralism' developed by combining the late 19th–20th century political term 'neutralism' (from English 'neutral' < Old French 'neutre' < Latin 'neuter') with the productive prefix 'anti-' (from Greek), yielding the modern English compound 'antineutralism'.

Initially the roots meant 'against' (anti-) and 'neither'/'not either' (neuter), but as a compound the word came to mean 'opposition to neutrality' in a political/diplomatic sense.