'unchangeably' originates from the word 'unchangeable', which is derived from the prefix 'un-' meaning 'not', and the root 'change', from Old French 'changier', meaning 'to alter'.

'unchangeable' evolved from the Old French word 'changier', which transformed into the Middle English 'chaungen', eventually becoming the modern English 'change'.

Initially, it meant 'not able to be altered', and this meaning has largely remained the same in modern usage.