The Collaborative International Dictionary of English v.0.48:

Exceptional \Ex*cep"tion*al\, a. [Cf. F. exceptionnel.]
   Forming an exception; not ordinary; uncommon; rare; hence,
   better than the average; superior. --Lyell.
   [1913 Webster]

         This particular spot had exceptional advantages.
                                                  --Jowett (Th.
                                                  )
   -- Ex*cep"tion*al*ly, adv.
   [1913 Webster]

WordNet (r) 3.0 (2006):

exceptionally
    adv 1: to an exceptional degree; "it worked exceptionally well"

Moby Thesaurus II by Grady Ward, 1.0:

84 Moby Thesaurus words for "exceptionally":
   abundantly, acutely, amazingly, amply, astonishingly, awesomely,
   beguilingly, bewilderingly, choose, cite, conspicuously, copiously,
   cull, eminently, emphatically, enigmatically, especially,
   exceedingly, excerpt, exquisitely, extract, extraordinarily,
   extremely, exuberantly, fabulously, famously, fantastically,
   fascinatingly, generously, glaringly, glean, hugely, impressively,
   incomprehensibly, inconceivably, incredibly, ineffably, intensely,
   magically, magnanimously, magnificently, markedly, marvelously,
   miraculously, nobly, notably, outlandishly, parlous, particularly,
   peculiarly, phenomenally, pick, pick out, pointedly, preeminently,
   prodigiously, profusely, prominently, pronouncedly, puzzlingly,
   quote, remarkably, richly, select, sensationally, signally, single,
   singularly, splendidly, strangely, strikingly, stupendously,
   superlatively, surpassingly, surprisingly, uncommonly,
   unimaginably, unspeakably, unusually, vitally, wonderfully,
   wondrous, wondrously, worthily