The Collaborative International Dictionary of English v.0.48:

Fiery \Fi"er*y\ (? or ?), a. [Formerly written firy, fr. fire.]
   1. Consisting of, containing, or resembling, fire; as, the
      fiery gulf of Etna; a fiery appearance.
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            And fiery billows roll below.         --I. Watts.
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   2. Vehement; ardent; very active; impetuous.
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            Hath thy fiery heart so parched thine entrails?
                                                  --Shak.
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            The fiery spirit of his forefathers.  --W. Irwing.
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   3. Passionate; easily provoked; irritable.
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            You know the fiery quality of the duke. --Shak.
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   4. Unrestrained; fierce; mettlesome; spirited.
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            One curbed the fiery steed.           --Dryden.
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   5. heated by fire, or as if by fire; burning hot; parched;
      feverish. --Pope.
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            The sword which is made fiery.        --Hooker.
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   Fiery cross, a cross constructed of two firebrands, and
      pitched upon the point of a spear; formerly in Scotland
      borne by a runner as a signal for the clan to take up
      arms. --Sir W. Scott.
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WordNet (r) 3.0 (2006):

fiery
    adj 1: characterized by intense emotion; "ardent love"; "an
           ardent lover"; "a fervent desire to change society"; "a
           fervent admirer"; "fiery oratory"; "an impassioned
           appeal"; "a torrid love affair" [syn: ardent,
           fervent, fervid, fiery, impassioned, perfervid,
           torrid]
    2: like or suggestive of fire; "a fiery desert wind"; "an
       igneous desert atmosphere" [syn: fiery, igneous]
    3: very intense; "a fiery temper"; "flaming passions" [syn:
       fiery, flaming]

Moby Thesaurus II by Grady Ward, 1.0:

212 Moby Thesaurus words for "fiery":
   Titian, Titian-red, abandoned, ablaze, accendible, afire, aflame,
   aglow, algetic, alight, angry, ardent, beany, blaring, blazing,
   boiling, boiling over, breathless, bricky, brilliant, broiling,
   burnable, burning, burning with excitement, cardinal, carmine,
   carnation, carnelian, cerise, chafed, cherry, cherry-colored,
   cherry-red, combustible, combustive, committed, conflagrant,
   conflagrative, cordial, crimson, damask, dedicated, delirious,
   devoted, devout, drunk, eager, earnest, edgy, emphatic,
   enthusiastic, excitable, excited, exciting, explosive, exuberant,
   faithful, fanatic, febrile, ferruginous, fervent, fervid,
   festering, fevered, feverish, feverous, fierce, fire-red, firelike,
   flame-colored, flame-red, flaming, flammable, flaring, flushed,
   furious, galled, glaring, gleaming, glowing, gules, hard-core,
   hasty, headlong, hearty, heated, hectic, het up, high-spirited,
   hot, hot-blooded, hot-tempered, hotheaded, hyperpyretic,
   hyperthermic, igneous, ignited, impassioned, impetuous, impulsive,
   in a fever, in earnest, in flames, in rut, incandescent,
   incarmined, inflamed, inflammable, infrared, intense, intent,
   intent on, intoxicated, irascible, iron-red, irritable, irritated,
   keen, lake-colored, laky, lateritious, lively, lobster-red, loyal,
   luminous, lurid, madcap, maroon, mettlesome, on fire, overheated,
   passionate, peppery, perfervid, port-wine, precipitate, provoking,
   puce, pyretic, pyric, quick, quick-tempered, radiant, rankling,
   raw, red, red-dyed, red-hot, red-looking, reddened, reddish,
   reddish-amber, reddish-brown, resolute, rubicund, rubiginous,
   rubric, rubricose, ruby, ruby-colored, ruby-red, ruddied, ruddy,
   rufescent, rufous, rust, rust-red, rusty, scalding, scarlet,
   scorching, seething, sensitive, serious, sexually excited,
   short-tempered, simmering, sincere, sizzling, smarting, sore,
   spirited, spunky, stammel, steaming, steamy, stimulating, stirring,
   stormy, tempestuous, tender, tile-red, tingling, tornadic, torrid,
   totally committed, touchy, unrestrained, urgent, vehement,
   vermilion, vigorous, vinaceous, violent, volcanic, warm, white-hot,
   wild, wine, wine-colored, wine-red, zealous