What is the meaning of secret?

noun

• Something that should remain hidden from others (especially information that is not to be passed on. )
  • usage: "the combination to the safe was a secret"; "he tried to keep his drinking a secret"
• Information known only to a special group.
  • usage: "the secret of Cajun cooking"
  • synonyms: arcanum
• Something that baffles understanding and cannot be explained.
  • usage: "how it got out is a mystery"; "it remains one of nature's secrets"
  • synonyms: mystery, enigma, closed book

adjective

• Not open or public; kept private or not revealed.
  • usage: "a secret formula"; "secret ingredients"; "secret talks"
• Conducted with or marked by hidden aims or methods.
  • usage: "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"
  • synonyms: clandestine, cloak-and-dagger, hole-and-corner, hugger-mugger, hush-hush, surreptitious, undercover, underground
• Not openly made known.
  • usage: "a secret marriage"; "a secret bride"
  • synonyms: unavowed
• Communicated covertly.
  • usage: "their secret signal was a wink"; "secret messages"
• Not expressed.
  • usage: "secret (or private) thoughts"
  • synonyms: private
• Designed to elude detection.
  • usage: "a hidden room or place of concealment such as a priest hole"; "a secret passage"; "the secret compartment in the desk"
  • synonyms: hidden
• Hidden from general view or use.
  • usage: "a privy place to rest and think"; "a secluded romantic spot"; "a secret garden"
  • synonyms: privy, secluded
• Of information. ( given in confidence or in secret)
  • usage: "this arrangement must be kept confidential"; "their secret communications"
  • synonyms: confidential
• Indulging only covertly.
  • usage: "a secret alcoholic"
• Having an import not apparent to the senses nor obvious to the intelligence; beyond ordinary understanding.
  • usage: "mysterious symbols"; "the mystical style of Blake"; "occult lore"; "the secret learning of the ancients"
  • synonyms: mysterious, mystic, mystical, occult, orphic
• The next to highest level of official classification for documents. .