Synonyms:
- arcane,
- cabalistic,
- censored,
- clandestine,
- classified,
- close,
- closed,
- concealed,
- covert,
- cryptic,
- dark,
- enigmatic,
- esoteric,
- hermetic,
- hidden,
- hugger-mugger,
- hugger-muggery,
- hush,
- latent,
- mysterious,
- occult,
- restricted,
- secret,
- secretiveness,
- secretness,
- silence,
- smothered,
- stifled,
- suppressed,
- top secret,
- ulterior,
- unbreatheable,
- under security,
- under wraps,
- under-the-table,
- undisclosable,
- undisclosed,
- undivulgable,
- undivulged,
- unrevealable,
- unrevealed,
- unspoken,
- untellable,
- untold,
- unutterable,
- unuttered,
- unwhisperable