nouns
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"
is a type of (narrower)
a message received and understood
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"
adjectives
not open or public; kept private or not revealed
"a secret formula"; "secret ingredients"; "secret talks"
is similar to
hidden on any grounds for any motive
"a concealed weapon"; "a concealed compartment in his briefcase"
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"
not openly made known
"a secret marriage"; "a secret bride"
communicated covertly
"their secret signal was a wink"; "secret messages"
is similar to
secret or hidden; not openly practiced or engaged in or shown or avowed
"covert actions by the CIA"; "covert funding for the rebels"
not expressed
"secret (or private) thoughts"
designed to elude detection
"a hidden room or place of concealment such as a priest hole"; "a secret passage"; "the secret compartment in the desk"
hidden from general view or use
"a privy place to rest and think"; "a secluded romantic spot"; "a secret garden"
(of information) given in confidence or in secret
"this arrangement must be kept confidential"; "their secret communications"
indulging only covertly
"a secret alcoholic"
is similar to
secret or hidden; not openly practiced or engaged in or shown or avowed
"covert actions by the CIA"; "covert funding for the rebels"
having an import not apparent to the senses nor obvious to the intelligence; beyond ordinary understanding
"mysterious symbols"; "the mystical style of Blake"; "occult lore"; "the secret learning of the ancients"
the next to highest level of official classification for documents
is similar to
official classification of information or documents; withheld from general circulation
"thousands of classified documents have now been declassified"