'mephitic' originates from Latin, specifically the word 'mephiticus', where 'mephitis' meant 'noxious exhalation' (a poisonous or pestilential vapor).

'mephitic' changed from Latin 'mephiticus' and the noun 'mephitis' and eventually became the modern English word 'mephitic' via Middle English.

Initially, it meant 'relating to or like a noxious exhalation,' but over time it evolved into its current meaning of 'foul-smelling and noxious.'