WordNet

the next to highest level of official classification for documents
information known only to a special group; "the secret of Cajun cooking" (同)arcanum
something that should remain hidden from others (especially information that is not to be passed on); "the combination to the safe was a secret"; "he tried to keep his drinking a secret"
not expressed; "secret (or private) thoughts" (同)private
communicated covertly; "their secret signal was a wink"; "secret messages"
indulging only covertly; "a secret alcoholic"
not open or public; kept private or not revealed; "a secret formula"; "secret ingredients"; "secret talks"
place out of sight; keep secret; "The money was secreted from his children"
generate and separate from cells or bodily fluids; "secrete digestive juices"; "release a hormone into the blood stream" (同)release
amide combining the amino group of one amino acid with the carboxyl group of another; usually obtained by partial hydrolysis of protein

PrepTutorEJDIC

『秘密の』,人目につかない / 《名詞の前にのみ用いて》(人・組織などが)秘かに活動する,(感情などが)表に出ない / 《補語にのみ用いて》《話》(人が)(…を)ないしょにする《+『about』+『名』》 / 『秘密』[の事],隠し事,ないしょの話 / 神秘,不思議 / 《単数形で》(…の)『秘けつ』,かぎ《+『of』+『名』(do『ing』)》,(…への)秘けつ《+『to』+『名』》
〈ホルモン・樹液など〉‘を'分泌(ぶんぴつ)する
…‘を'隠す,秘密の場所にしまう