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):

furious
    adj 1: marked by extreme and violent energy; "a ferocious
           beating"; "fierce fighting"; "a furious battle" [syn:
           ferocious, fierce, furious, savage]
    2: marked by extreme anger; "the enraged bull attached";
       "furious about the accident"; "a furious scowl"; "infuriated
       onlookers charged the police who were beating the boy";
       "could not control the maddened crowd" [syn: angered,
       enraged, furious, infuriated, maddened]
    3: (of the elements) as if showing violent anger; "angry clouds
       on the horizon"; "furious winds"; "the raging sea" [syn:
       angry, furious, raging, tempestuous, wild]

Moby Thesaurus II by Grady Ward, 1.0:

189 Moby Thesaurus words for "furious":
   Dionysiac, abandoned, accident-prone, acute, amok, anarchic, angry,
   at fever pitch, bacchic, bellowing, berserk, bewildered,
   blustering, blusterous, blustery, boiling, breakneck, browned off,
   careless, carried away, chaotic, coarse, concentrated, corybantic,
   crazed, cursory, cutting, delirious, demented, demoniac, desperate,
   devil-may-care, dirty, distracted, drastic, ecstatic, enraged,
   enraptured, enthusiastic, excessive, excited, exorbitant,
   expeditious, exquisite, fanatic, fanatical, febrile, feral,
   ferocious, festinate, feverish, fierce, fiery, fighting mad,
   flying, frantic, frenetic, frenzied, fulminating, fuming, great,
   haggard, harum-scarum, hasty, headlong, hectic, hellish, hog-wild,
   hopping mad, hotheaded, howling, hurried, hysteric, hysterical,
   immediate, immoderate, impetuous, in a rage, in a tizzy,
   in a transport, in hysterics, incensed, infatuated, infuriate,
   infuriated, inordinate, insane, insensate, instant, intemperate,
   intense, intoxicated, irate, irrational, keen, last-minute,
   like one possessed, livid, mad, maddened, madding, maenadic,
   maniac, maniacal, mindless, on the spot, orgasmic, orgastic,
   orgiastic, outrageous, overanxious, overdesirous, overeager,
   overenthusiastic, overzealous, pandemoniac, passing, passionate,
   perfervid, piercing, pissed off, possessed, precipitant,
   precipitate, precipitous, prompt, provoked, quick, rabid, raging,
   ramping, ranting, ravening, raving, raving mad, ravished, reckless,
   rigorous, rip-roaring, roaring, roaring mad, rough, running mad,
   running wild, savage, severe, sharp, simmering, slap-bang,
   slapdash, snap, speedy, splitting, stark-raving mad, steaming,
   stimulated, storming, stormy, superficial, swift, tempestuous,
   terrible, tornadic, tough, transported, troublous, tumultuous,
   turbulent, ultrazealous, unconscionable, uncontrollable,
   unreasonable, unrestrained, up in arms, uproarious, upset, urgent,
   vehement, venomous, vicious, violent, virulent, volcanic, wanton,
   wild, wild-eyed, wild-looking, wrathful, wroth