'non-disclosure' originates from the prefix 'non-' meaning 'not' and the word 'disclosure' from Latin 'disclosura', where 'dis-' meant 'apart' and 'claudere' meant 'to close'.

'disclosura' transformed into the Old French word 'desclore', and eventually became the modern English word 'disclosure'.

Initially, it meant 'to open or reveal', but over time it evolved into its current meaning of 'not revealing'.