'unidentifiable' originates from the prefix 'un-' meaning 'not' and the word 'identifiable', which comes from 'identify', derived from Latin 'identificare', where 'ident-' meant 'same' and 'facere' meant 'to make'.

'identificare' transformed into the French word 'identifier', and eventually became the modern English word 'identify', leading to 'identifiable' and then 'unidentifiable'.

Initially, it meant 'not able to be made the same', but over time it evolved into its current meaning of 'not able to be identified'.