'antipedobaptist' originates from modern English, specifically a compound formed from the prefix 'anti-' (from Greek 'anti', meaning 'against'), the combining form 'pedo-' (from Greek 'pais/paidos', meaning 'child'), and 'baptist' (from Greek 'baptizō'/'baptistēs', meaning 'to dip/immerse' or 'one who baptizes').

'antipedobaptist' was formed in English by joining 'anti-' + 'paedo/pedo-' + 'baptist'; earlier writings sometimes show the variant spelling 'anti-paedobaptist' (with hyphen and British 'ae'), and later the form without hyphens 'antipedobaptist' became used in some contexts.

Initially, the term meant 'one opposed to the practice of infant baptism', and over time it has retained that specific doctrinal sense without major change.