[1] : WordNet (r) 2.0

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

[2] : Moby Thesaurus II by Grady Ward, 1.0

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

Rosa >> R Words
Rosa, definition of term: Rosa
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