'antiabortion' is a compound of the prefix 'anti-' and the noun 'abortion'. 'Anti-' originates from Greek 'anti', where 'anti-' meant 'against'. 'Abortion' originates from Latin 'abortio' (from 'aboriri'), where the root related to 'to miscarry' or 'to fail to be born'.

'Abortion' came into English via Latin 'abortio' and Old French forms such as 'avortement', later Middle English 'abortion'. The prefix 'anti-' (from Greek) was attached in modern English to form the hyphenated compound 'anti-abortion', which later also appears as the closed compound 'antiabortion'.

The combined term initially and consistently meant 'against abortion' (opposition to abortion). Over time it has remained semantically stable but has come to denote not only personal opposition but also organized movements and political positions.