'untrimmed' originates from the prefix 'un-' meaning 'not' and the word 'trim', which comes from Middle English 'trimmen', meaning 'to make neat'.

'trimmen' transformed into the modern English word 'trim', and with the addition of the prefix 'un-', it became 'untrimmed'.

Initially, 'trim' meant 'to make neat', and 'untrimmed' has consistently meant 'not made neat'.