'unsalable' originates from the prefix 'un-' meaning 'not' and the word 'salable' which comes from the Latin word 'salabilis', meaning 'able to be sold'.

'salabilis' transformed into the Old French word 'salable', and eventually became the modern English word 'salable'. The prefix 'un-' was added to form 'unsalable'.

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