'confidential' originates from Latin, specifically the word 'confidentia,' where 'con-' meant 'with' and 'fidere' meant 'to trust.'

'confidentia' transformed into the French word 'confidentiel,' and eventually became the modern English word 'confidential' through Middle English.

Initially, it meant 'trusting or having faith in someone,' but over time it evolved into its current meaning of 'intended to be kept secret or private.'