'anti-Christian' originates from the Greek prefix 'anti-' (ἀντί), where 'anti-' meant 'against', combined with Late Latin 'Christianus' (from Greek 'Christianos') meaning 'follower of Christ'.

'anti-' (from Greek) was attached to 'Christian' (from Late Latin 'Christianus', via Greek 'Christianos' and earlier forms meaning 'follower of Christ') to form the compound adjective 'anti-Christian' in English, recorded in modern usage from the 19th century onwards.

Initially it described being 'against Christians or Christianity' in a doctrinal or political sense; over time it has kept that core sense but also broadened to cover cultural, social, or personal hostility toward Christianity.