The Collaborative International Dictionary of English v.0.48:

Extraordinarily \Ex*traor"di*na*ri*ly\, adv.
   In an extraordinary manner or degree.
   [1913 Webster]

WordNet (r) 3.0 (2006):

extraordinarily
    adv 1: extremely; "she was inordinately smart"; "it will be an
           extraordinarily painful step to negotiate" [syn:
           inordinately, extraordinarily]

Moby Thesaurus II by Grady Ward, 1.0:

67 Moby Thesaurus words for "extraordinarily":
   abundantly, acutely, amazingly, amply, astonishingly, awesomely,
   beguilingly, bewilderingly, conspicuously, copiously, eminently,
   emphatically, enigmatically, exceptionally, exquisitely,
   exuberantly, fabulously, famously, fantastically, fascinatingly,
   generously, glaringly, impressively, incomprehensibly,
   inconceivably, incredibly, ineffably, intensely, magically,
   magnanimously, magnificently, markedly, marvelously, miraculously,
   nobly, notably, outlandishly, particularly, peculiarly,
   phenomenally, pointedly, preeminently, prodigiously, profusely,
   prominently, pronouncedly, puzzlingly, remarkably, richly,
   sensationally, signally, singularly, splendidly, strangely,
   strikingly, stupendously, superlatively, surpassingly,
   surprisingly, uncommonly, unimaginably, unspeakably, unusually,
   wonderfully, wondrous, wondrously, worthily