'backslide' originates from Middle English, specifically the word 'backsliden,' where 'back' meant 'to the rear' and 'slide' meant 'to slip or glide.'

'backsliden' transformed into the modern English word 'backslide' through the influence of Old English and Middle English.

Initially, it meant 'to slip backward,' but over time it evolved into its current meaning of 'to revert to a previous, less advanced state.'