'unassignable' originates from the prefix 'un-' meaning 'not' and the word 'assignable', which comes from the Latin 'assignare', meaning 'to mark out' or 'to allot'.

'assignare' transformed into the Old French word 'assigner', and eventually became the modern English word 'assign'. The prefix 'un-' was added to form 'unassignable'.

Initially, 'assignare' meant 'to allot or mark out', and 'unassignable' evolved to mean 'not capable of being assigned'.