'antichristian' originates from the prefix 'anti-' (from Greek 'antí' meaning 'against') combined with 'Christian' (from Late Latin 'Christianus', from Greek 'Christos' meaning 'anointed').

'antichristian' formed in English by combining 'anti-' + 'Christian' (attested from Early Modern English onward) to describe opposition to Christianity; it follows the regular pattern of English word-formation using the Greek/Latin prefix 'anti-'.

Initially used simply to denote opposition to Christ or Christians, the term has retained this core sense and is still used to mean 'against Christianity' or 'hostile to Christian beliefs'.