'antimatrimonialist' originates from a modern English composition: the prefix 'anti-' (from Greek 'anti', meaning 'against'), the adjective 'matrimonial' (from Latin 'matrimonium', meaning 'marriage'), and the agentive suffix '-ist' (from Greek/Latin via French, indicating 'one who practices or advocates').

'matrimonial' derives from Latin 'matrimonium' (marriage) and entered English via Old French/Medieval Latin forms; 'anti-' is from Greek 'anti-' meaning 'against'; the suffix '-ist' (from Greek '-istēs' through Latin/French) was added in English to form agent nouns, producing 'antimatrimonialist' as a coined modern English term.

Initially the components meant 'against' + 'marriage' + 'one who' and the compound has consistently retained the meaning 'a person opposed to marriage' in modern usage, though the word itself is a relatively rare, coined term.