sub rosa

sub rosa
    adv 1: in secret or covertly; "held a meeting sub rosa to avoid
           general criticism"
    

26 Moby Thesaurus words for "sub rosa":
      behind the curtain, behind the scenes, behind the veil, by stealth,
      covertly, furtively, hugger-mugger, in a corner, in a whisper,
      in camera, in darkness, in hidlings, in secret, in the background,
      in the dark, nobody the wiser, privately, secretly, sotto voce,
      stealthily, surreptitiously, under the breath, under the rose,
      undercover, underground, with bated breath