'backfire' originates from English, specifically the combination of 'back' and 'fire', where 'back' meant 'the rear' and 'fire' meant 'flame/combustion'.

'backfire' developed from earlier two-word phrases such as 'back fire' used in reference to firearms and engines in the 18th–19th centuries and eventually became the single compound 'backfire' in modern English.

Initially it referred literally to 'a fire or explosion at the rear' (e.g. in engines or guns), but over time it evolved metaphorically into the current meaning of 'an action that produces an opposite or adverse result to that intended'.