secret

(noun) something that should remain hidden from others (especially information that is not to be passed on). Examples: "The combination to the safe was a secret." "He tried to keep his drinking a secret."

(noun) information known only to a special group. Synonyms: arcanum. Example: "The secret of cajun cooking."

(noun) something that baffles understanding and cannot be explained. Synonyms: mystery, enigma, closed book. Examples: "How it got out is a mystery." "It remains one of nature's secrets."

(adj) not open or public; kept private or not revealed. Examples: "A secret formula." "Secret ingredients." "Secret talks."

(adj) conducted with or marked by hidden aims or methods. Synonyms: clandestine, cloak-and-dagger, hole-and-corner(prenominal), hugger-mugger, hush-hush, surreptitious, undercover, underground. Examples: "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."

(adj) not openly made known. Synonyms: unavowed. Examples: "A secret marriage." "A secret bride."

(adj) communicated covertly. Examples: "Their secret signal was a wink." "Secret messages."

(adj) not expressed. Synonyms: private. Example: "Secret (or private) thoughts."

(adj) designed to elude detection. Synonyms: hidden. Examples: "A hidden room or place of concealment such as a priest hole." "A secret passage." "The secret compartment in the desk."

(adj) hidden from general view or use. Synonyms: privy, secluded. Examples: "A privy place to rest and think." "A secluded romantic spot." "A secret garden."

(adj) (of information) given in confidence or in secret. Synonyms: confidential. Examples: "This arrangement must be kept confidential." "Their secret communications."

(adj) indulging only covertly. Example: "A secret alcoholic."

(adj) having an import not apparent to the senses nor obvious to the intelligence; beyond ordinary understanding. Synonyms: mysterious, mystic, mystical, occult, orphic. Examples: "Mysterious symbols." "The mystical style of blake." "Occult lore." "The secret learning of the ancients."

(adj) the next to highest level of official classification for documents.