'backslidden' originates from English, formed from the verb 'backslide' with the participial suffix '-en' (indicating a past participle/adjective).

'backslide' comes from the combination of 'back' (Old English 'bæc') + 'slide' (Old English 'slīdan', 'to slip or glide'); the past forms 'backslid' and the participial variant 'backslidden' developed later in Early Modern English.

Originally related to the literal idea of 'sliding backward,' it came to be used figuratively for 'lapse or relapse into former (often bad) ways,' a sense that became common in religious and moral contexts.