'avenger' originates from Old French, specifically the word 'avengier,' where 'a-' meant 'to' and 'vengier' meant 'to take revenge.'

'avengier' transformed into the Middle English word 'avengen,' and eventually became the modern English word 'avenge' and its derivative 'avenger.'

Initially, it meant 'to take revenge,' and this meaning has largely remained the same in modern usage.