'seizure-preventive' originates from modern English, formed by combining the noun 'seizure' and the adjective 'preventive'. 'Seizure' itself comes into English via Old French 'seisir' meaning 'to take possession' (used in Middle English as forms like 'seisure'), while 'preventive' comes from Latin roots in 'praevenire' (prae- 'before' + venire 'to come') via Old French/Latin-derived forms.

'seizure' changed from Old French 'seisir' into Middle English forms such as 'seisure' and eventually the modern English 'seizure'; 'preventive' developed from Latin 'praevenire' -> Old French/Medieval Latin forms -> Middle/Modern English 'prevent' and the adjective 'preventive'. The compound 'seizure-preventive' is a modern English formation combining these elements to describe something that prevents seizures.

Initially, 'seizure' referred to the act of seizing or taking possession and 'preventive' meant 'tending to prevent' (coming before); over time, when combined as 'seizure-preventive' the meaning became specialized to 'intended to prevent epileptic seizures' in medical contexts.