secrets

(noun) something that should remain hidden from others (especially information that is not to be passed on). Synonyms: secret. 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: secret, arcanum. Example: "The secret of cajun cooking."

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