'unendorsed' originates from the prefix 'un-' meaning 'not' and the verb 'endorse', which comes from the Latin word 'indorsare', meaning 'to write on the back'.

'indorsare' transformed into the Old French word 'endosser', and eventually became the modern English word 'endorse'.

Initially, 'endorse' meant 'to write on the back', but over time it evolved into its current meaning of 'to approve or support'.