The Collaborative International Dictionary of English v.0.48:

Nobly \No"bly\, adv.
   1. Of noble extraction; as, nobly born or descended.
      [1913 Webster]

   2. In a noble manner; with greatness of soul; heroically;
      with magnanimity; as, a deed nobly done.
      [1913 Webster]

   3. Splendidly; magnificently.
      [1913 Webster]

   Syn: Illustriously; honorably; magnanimously; heroically;
        worthly; eminently; grandly.
        [1913 Webster]

WordNet (r) 3.0 (2006):

nobly
    adv 1: in a noble manner; "she has behaved nobly"

Moby Thesaurus II by Grady Ward, 1.0:

106 Moby Thesaurus words for "nobly":
   abundantly, acutely, amazingly, amply, astonishingly, awesomely,
   bigheartedly, blamelessly, chivalrously, conscientiously,
   conspicuously, copiously, creditably, decently, elaborately,
   elegantly, eminently, emphatically, erectly, estimably,
   exceptionally, exquisitely, extraordinarily, extravagantly,
   exuberantly, famously, fastidiously, generously, glaringly,
   gloriously, grandiosely, grandly, gravely, greatheartedly,
   handsomely, high-mindedly, honestly, honorably, immaculately,
   imposingly, impressively, incredibly, intensely, irreproachably,
   knightly, largeheartedly, liberally, loftily, luxuriously,
   magically, magisterially, magnanimously, magnificently,
   majestically, markedly, marvelously, meticulously, morally,
   notably, openhandedly, particularly, peculiarly, pointedly,
   preeminently, profusely, prominently, pronouncedly, proudly,
   punctiliously, purely, regally, remarkably, reputably, respectably,
   richly, righteously, royally, scrupulously, sedately, signally,
   singularly, soberly, solemnly, splendaciously, splendidly,
   splendiferously, stainlessly, stately, strikingly, sumptuously,
   superbly, superlatively, surpassingly, surprisingly, uncommonly,
   unimpeachably, unspottedly, unusually, uprightly, upstandingly,
   venerably, virtuously, with dignity, wonderfully, wondrous,
   worthily