privacy (n.)

1590s, "a private matter, a secret;" c. 1600 as "seclusion," from private (adj.) + abstract noun suffix -cy. Meaning "state of freedom from intrusion" is from 1814. Earlier was privatie (late 14c. as "secret, mystery;" c. 1400 as "a secret, secret deed; solitude, privacy"), from Old French privauté.