'unchanging' originates from the prefix 'un-' meaning 'not' and the word 'changing' from the verb 'change', which comes from Old French 'changier', meaning 'to alter'.

'changier' transformed into the Middle English word 'chaungen', and eventually became the modern English word 'change'.

Initially, it meant 'to alter or make different', but over time it evolved into its current meaning of 'remaining the same'.