'antiepileptic' originates from a combination of the Greek-derived prefix 'anti-' and 'epileptic'. Specifically, 'anti-' comes from Greek 'antí' meaning 'against', and 'epileptic' ultimately comes from Greek 'epilepsia' meaning 'seizure'.

'epileptic' entered English via Latin/Medieval Latin from Greek 'epilēpsia' (seizure) and the adjective form 'epileptikos'; the modern compound 'antiepileptic' was formed in English by adding the prefix 'anti-' to 'epileptic' to denote something countering epilepsy (e.g., a medicine).

Initially the elements meant 'against' + 'seizure'; over time the compound came to mean not only 'against epilepsy' in a general sense but specifically 'preventing or treating epileptic seizures' and also came to be used as a noun for drugs that do so.