ADVERB (3)

1. (of the elements) in a wild and stormy manner;
- Example: "winds were blowing furiously"

2. in a manner marked by extreme or violent energy;
- Example: "the boys fought furiously"
- Example: "she went peddling furiously up the narrow street"

3. in an impassioned or very angry manner;
- Example: "she screamed furiously at her tormentors"

The Collaborative International Dictionary of English v.0.48:

Furious \Fu"ri*ous\, a. [L. furiosus, fr. furia rage, fury: cf.
   F. furieux. See Fury.]
   1. Transported with passion or fury; raging; violent; as, a
      furious animal.
      [1913 Webster]

   2. Rushing with impetuosity; moving with violence; as, a
      furious stream; a furious wind or storm.

   Syn: Impetuous; vehement; boisterous; fierce; turbulent;
        tumultuous; angry; mad; frantic; frenzied. --
        Fu"ri*ous*ly, adv. -- Fu"ri*ous*ness, n.
        [1913 Webster]

WordNet (r) 3.0 (2006):

furiously
    adv 1: (of the elements) in a wild and stormy manner; "winds
           were blowing furiously"
    2: in a manner marked by extreme or violent energy; "the boys
       fought furiously"; "she went peddling furiously up the narrow
       street"
    3: in an impassioned or very angry manner; "she screamed
       furiously at her tormentors"

Moby Thesaurus II by Grady Ward, 1.0:

94 Moby Thesaurus words for "furiously":
   a corps perdu, all to pieces, amain, angrily, apace, at once,
   by forced marches, carelessly, cursorily, deliriously, demonically,
   desperately, distractedly, expeditiously, fanatically, feverishly,
   fiercely, frantically, frenetically, frenziedly, hand over fist,
   happen what may, hastily, head over heels, headfirst, headforemost,
   headlong, heatedly, heedlessly, heels over head, helter-skelter,
   holus-bolus, hotfoot, hotheadedly, hotly, hurriedly, hurry-scurry,
   immediately, impetuously, in anger, in hot blood, in passing,
   indignantly, infuriatedly, infuriately, insensately, instantly,
   irately, like blazes, like crazy, like fury, like mad,
   like one possessed, madly, mindlessly, on the run, overeagerly,
   overenthusiastically, overzealously, pell-mell, precipitantly,
   precipitately, precipitously, promptly, quickly, rabidly,
   ramble-scramble, recklessly, rigorously, riotously, severely,
   slam-bang, slap-bang, slapdash, speedily, stormily, superficially,
   swiftly, tempestuously, troublously, turbulently, uncontrollably,
   uproariously, vehemently, venomously, violently, virulently,
   wantonly, wildly, with a rush, with a vengeance, with all haste,
   with dispatch, with haste