'unholster' originates from Modern English, formed by the prefix 'un-' plus the noun 'holster'.

'holster' entered English from Dutch or Low German forms such as 'holster' in the early modern period, meaning a case or covering for a pistol; English then formed 'un-' + 'holster' to create 'unholster'.

Initially it specifically meant 'to remove from a holster', and it has retained that core meaning in modern usage.