sur·rep·ti·tious /ˌsɝəpˈtɪʃəs, ˌsʌrəp, səˌrɛp-/
  (a.)祕密的,暗中的,偷偷摸摸的
  Sur·rep·ti·tious a.  Done or made by stealth, or without proper authority; made or introduced fraudulently; clandestine; stealthy; as, a surreptitious passage in an old manuscript; a surreptitious removal of goods. -- Sur*rep*ti*tious*ly, adv.
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  surreptitious
       adj 1: marked by quiet and caution and secrecy; taking pains to
              avoid being observed; "a furtive manner"; "a lurking
              prowler"; "a sneak attack"; "stealthy footsteps"; "a
              surreptitious glance at his watch"; "someone skulking
              in the shadows" [syn: furtive, lurking, skulking,
               sneak(a), sneaky, stealthy]
       2: conducted with or marked by hidden aims or methods;
          "clandestine intelligence operations"; "cloak-and-dagger
          activities behind enemy lines"; "hole-and-corner
          intrigue"; "secret missions"; "a secret agent"; "secret
          sales of arms"; "surreptitious mobilization of troops";
          "an undercover investigation"; "underground resistance"
          [syn: clandestine, cloak-and-dagger, hole-and-corner(a),
           hugger-mugger, hush-hush, on the quiet(p), secret,
           undercover, underground]