secret (Noun) — Something that should remain hidden from others (especially information that is not to be passed on). ex. "the combination to the safe was a secret" ex. "he tried to keep his drinking a secret"
secret (Noun) — Information known only to a special group. ex. "the secret of Cajun cooking"
secret (Noun) — Something that baffles understanding and cannot be explained. ex. "it remains one of nature's secrets"
secret (Adjective) — Not open or public; kept private or not revealed. ex. "a secret formula" ex. "secret ingredients" ex. "secret talks"
secret (Adjective) — Conducted with or marked by hidden aims or methods. ex. "secret missions" ex. "a secret agent" ex. "secret sales of arms"
secret (Adjective) — Not openly made known. ex. "a secret marriage"
secret (Adjective) — Communicated covertly. ex. "their secret signal was a wink" ex. "secret messages"
secret (Adjective) — Not expressed. ex. "secret thoughts"
secret (Adjective) — Designed to elude detection. ex. "a secret passage" ex. "the secret compartment in the desk"
secret (Adjective) — Hidden from general view or use. ex. "a secret garden"
secret (Adjective) — (of information) given in confidence or in secret. ex. "their secret communications"
secret (Adjective) — Indulging only covertly. ex. "a secret alcoholic"
secret (Adjective) — Having an import not apparent to the senses nor obvious to the intelligence; beyond ordinary understanding. ex. "the secret learning of the ancients"
secret (Adjective) — The next to highest level of official classification for documents.