'imperil' originates from Middle English, specifically the word 'empeiren,' where 'em-' meant 'in' and 'peiren' meant 'to make worse.'

'empeiren' transformed into the Old French word 'empirer,' and eventually became the modern English word 'imperil' through Middle English.

Initially, it meant 'to make worse or deteriorate,' but over time it evolved into its current meaning of 'to put in danger.'