'antitumoral' originates from Greek 'anti' (prefix) meaning 'against', combined with Latin 'tumor' meaning 'a swelling' and the adjectival suffix '-al'.

'tumor' comes from Latin 'tumor' (from the verb 'tumēre', 'to swell') and entered English via Old French 'tumeur' and Middle English; 'antitumoral' was formed in modern English by prefixing 'anti-' to 'tumor' (with '-al' to make an adjective).

Initially the elements referred literally to 'against swelling', but over time the combined form has come to mean specifically 'active against tumors' or 'inhibiting tumor growth'.