The Oxford Thesaurus An A-Z Dictionary of Synonyms - secretadj.

1) concealed, hidden, private, covert, shrouded, clandestine; confidential, covert, quiet, under cover, secretive, unpublishable, unpublished, Colloq hush-hush: There is a secret passageway leading from the cave to the cove. Keep secret what I shall tell you. She revealed to me her most secret desires. 2) cryptic, private, arcane, mysterious, incomprehensible, esoteric, recondite, abstruse; cryptographic, encrypted, encoded: We used to communicate by secret code. Did you receive my secret message? --n. 3) private or confidential matter or affair, mystery: If I tell you my secret will you tell me yours? 4 in secret. privately, confidentially, secretly, on the q.t. or Q.T.; surreptitiously, under cover, by stealth, stealthily, furtively, quietly, on the sly, clandestinely: The office manager told me in secret that John was going to resign. They see one another in secret.