'unsheathe' originates from Old English, specifically the prefix 'un-' plus the word 'sheathe' (from Old English 'scēað'), where 'un-' meant 'reverse/remove' and 'scēað' meant 'covering' or 'sheath'.

'unsheathe' changed from Middle English forms such as 'unsheten' (formed by adding 'un-' to Middle English 'sheten/shetene'/'sheten') and eventually became the modern English word 'unsheathe'.

Initially it meant 'to take out of a sheath', and over time it has retained that core sense; it is also used figuratively to mean 'reveal' or 'bring forth'.