'unserviceable' originates from the prefix 'un-' meaning 'not' and the word 'serviceable', which comes from the Old French 'serviciable', meaning 'useful'.

'serviciable' transformed into the Middle English word 'servisable', and eventually became the modern English word 'serviceable', with 'un-' added to form 'unserviceable'.

Initially, it meant 'not useful or not able to be used', and this meaning has largely remained the same in modern usage.