'undead' originates from Old English, specifically the word 'undēad,' where 'un-' meant 'not' and 'dēad' meant 'dead.'

'undēad' transformed into the Middle English word 'undede,' and eventually became the modern English word 'undead.'

Initially, it meant 'not dead,' but over time it evolved into its current meaning of 'neither alive nor dead, often in a supernatural context.'