'undisclosed' originates from the prefix 'un-' meaning 'not' and the verb 'disclose' from Latin 'discludere', where 'dis-' meant 'apart' and 'claudere' meant 'to close'.

'discludere' transformed into the Old French word 'desclore', and eventually became the modern English word 'disclose'.

Initially, 'disclose' meant 'to open or unlock', but over time it evolved into its current meaning of 'to reveal or make known'.