'backout' originates from English, specifically from the combination of 'back' (from Old English 'bæc') and 'out' (from Old English 'ūt'), where 'bæc' meant 'back/rear' and 'ūt' meant 'out'.

'backout' developed as a nominalization of the phrasal verb 'back out' (to move back or withdraw). The phrasal verb derives from earlier English elements 'back' + 'out'; the noun form (often written as one word) emerged in modern English and was increasingly used in the 20th century, later gaining a technical sense in computing as 'to roll back a change'.

Initially, the components conveyed the literal idea 'move back/away'; over time the phrasal verb came to mean 'withdraw from a commitment', and the noun 'backout' acquired both that figurative sense and a specialized technical sense of 'reversal/rollback' in computing.