'sever' originates from Old French, specifically the word 'sevrer', which in turn comes from Latin 'separare' meaning 'to separate'.

'separare' (Latin) changed into Old French 'sevrer' and through Middle English forms like 'severen' eventually became the modern English word 'sever'.

Initially, it meant 'to separate' in a general sense; over time it developed more specific senses such as 'to cut off' (physically) and 'to end a relationship or connection'.