'unimproved' originates from the prefix 'un-' meaning 'not' and the verb 'improve', which comes from the Latin word 'improbare', where 'in-' meant 'in' and 'probare' meant 'to test or prove'.

'improbare' transformed into the Old French word 'emprover', and eventually became the modern English word 'improve'. The prefix 'un-' was added to form 'unimproved'.

Initially, 'improve' meant 'to make better', and 'unimproved' has consistently meant 'not made better'.