Dictionary.net

information known only to a special group; "the secret of Cajun cooking"

conducted with or marked by hidden aims or methods; "clandestine intelligence operations"; "cloak-and-dagger activities behind enemy lines"; "hole-and-corner intrigue"; "secret missions"; "a secret agent"; "secret sales of arms"; "surreptitious mobilization of troops"; "an undercover investigation"; "underground resistance"

something that baffles understanding and cannot be explained; "how it got out is a mystery"; "it remains one of nature's secrets"

not expressed; "secret (or private) thoughts"

not open or public; kept private or not revealed; "a secret formula"; "secret ingredients"; "secret talks"

something that should remain hidden from others (especially information that is not to be passed on); "the combination to the safe was a secret"; "he tried to keep his drinking a secret"

not openly made known; "a secret marriage"; "a secret bride"

the next to highest level of official classification for documents

communicated covertly; "their a secret signal was a wink"; "secret messages"

information known only to a special group; "the secret of Cajun cooking"

something that baffles understanding and cannot be explained; "how it got out is a mystery"; "it remains one of nature's secrets"

not expressed; "secret (or private) thoughts"

not open or public; kept private or not revealed; "a secret formula"; "secret ingredients"; "secret talks"

something that should remain hidden from others (especially information that is not to be passed on); "the combination to the safe was a secret"; "he tried to keep his drinking a secret"

not openly made known; "a secret marriage"; "a secret bride"

the next to highest level of official classification for documents

Withdraw from general intercourse or notice; in retirement or secrecy; secluded.

Faithful to a secret; not inclined to divulge or betray confidence; secretive.

Separate; distinct.

Something studiously concealed; a thing kept from general knowledge; what is not revealed, or not to be revealed.

A thing not discovered; what is unknown or unexplained; a mystery.

The parts which modesty and propriety require to be concealed; the genital organs.

To keep secret.

Withdraw from general intercourse or notice; in retirement or secrecy; secluded.

Faithful to a secret; not inclined to divulge or betray confidence; secretive.

Separate; distinct.

Something studiously concealed; a thing kept from general knowledge; what is not revealed, or not to be revealed.

A thing not discovered; what is unknown or unexplained; a mystery.

The parts which modesty and propriety require to be concealed; the genital organs.

To keep secret.

Hidden or concealed; removed from sight; kept from general knowledge; mysterious; private: secret service, government detective service.

That which is purposely concealed or untold; something unknown; that which, when made known, makes something clear.

Put apart or separate: concealed from notice: removed from sight: unrevealed: hidden: secluded: retired: private: keeping secrets: reserved.

That which is concealed: anything unrevealed or unknown: privacy: a light flexible coat of chain-mail worn under the ordinary outer garments. Sir W. Scott.

Concealed; secluded; private; having secrets; reserved.

Something concealed.

Separate; hidden; private; secluded; close mouthed.

Something not to be told or not known.

An underlying reason.

Secretness.

Concealed from notice; private; unknown; occult; not apparent; known to God only.

Something studiously concealed; a thing not discovered; a silent spoken prayer in the service of the mass. In secret, in a private place. See Secern.

Concealed; hidden; kept from the view or knowledge of all except those concerned; not revealed; secluded; private; not apparent; occult; obscure; known to God alone.

Something studiously concealed; something undiscovered or unknown.

n. Something studiously concealed; a thing kept from general knowledge; —a thing not discovered; a mystery;—privacy; secrecy—with prefix in.