'undyed' originates from the prefix 'un-' meaning 'not' and the word 'dye', which comes from Old English 'dēag', meaning 'color'.

'dēag' transformed into the Middle English word 'deyen', and eventually became the modern English word 'dye'.

Initially, 'dye' meant 'to color', and 'undyed' has consistently meant 'not colored'.