secret

名秘密
形秘密の

undercover, hush-hush, covert, cloak-and-dagger, unknown, underground, hidden, furtive, confidential, unseen, unpublished, undisclosed, under wraps, shrouded, recondite, occult, mysterious, esoteric, disguised, cryptic, covered, conspiratorial, concealed, closet, classified, clandestine

se-(“apart, away”) + cernere(“to separate, sift”) = secernere(“to set apart, divide”)より

secrecy, secretary, secrete, secretion, secretive, secretively, secretiveness, secretly