'vitiate' originates from Latin, specifically the verb 'vitiare', where 'vitium' meant 'fault' or 'defect'.

'vitiate' came into English via Late Latin 'vitiatus' / 'vitiare' (and through medieval/early modern usage) and was adopted into Middle English in forms such as 'vitien'/'vitiaten' before becoming the modern English 'vitiate'.

Initially it meant 'to make faulty or defective', and over time it has come to be used more broadly as 'to spoil, impair, corrupt, or make invalid'.