The Collaborative International Dictionary of English v.0.48:

Fervent \Fer"vent\, a. [F. fervent, L. fervens, -entis. p. pr.
   of fervere o the boiling hot, to boil, glow.]
   1. Hot; glowing; boiling; burning; as, a fervent summer.
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            The elements shall melt with fervent heat. --2 Pet.
                                                  iii. 10.
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   2. Warm in feeling; ardent in temperament; earnest; full of
      fervor; zealous; glowing.
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            Not slothful in business; fervent in spirit. --Rom.
                                                  iii. 11.
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            So spake the fervent angel.           --Milton.
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            A fervent desire to promote the happiness of
            mankind.                              --Macaulay.
      -- Fer"vent*ly, adv. -- Fer"vent*ness, n.
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            Laboring fervently for you in prayers. --Col. iv.
                                                  12.
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WordNet (r) 3.0 (2006):

fervent
    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: extremely hot; "the fervent heat...merely communicated a
       genial warmth to their half-torpid systems"- Nathaniel
       Hawthorne; "set out...when the fervid heat subsides"- Frances
       Trollope [syn: fervent, fervid]

Moby Thesaurus II by Grady Ward, 1.0:

111 Moby Thesaurus words for "fervent":
   abandoned, ablaze, afire, animated, ardent, assiduous, blazing,
   boiling, boiling over, breathless, burning,
   burning with excitement, captivated, committed, cordial, dedicated,
   delirious, devoted, devout, diligent, drunk, eager, earnest,
   ecstatic, emotional, emphatic, energetic, enraptured, enthusiastic,
   excited, exciting, exuberant, faithful, fanatical, febrile, fervid,
   fevered, feverish, fiery, flaming, flushed, frantic, frenzied,
   glowing, hard, hardworking, heartfelt, hearty, heated, hectic,
   het up, hot, hot-blooded, hotheaded, impassioned, in earnest,
   in rut, indefatigable, industrious, inflamed, intense, intent,
   intent on, intoxicated, keen, laborious, lively, loyal, never idle,
   on fire, passionate, perfervid, pious, provoking, rapt, rapturous,
   red-hot, relentless, religious, resolute, responsive, sedulous,
   seething, serious, sexually excited, sincere, sleepless, spirited,
   steaming, steamy, stimulating, stirring, strenuous, tender,
   tireless, transported, unfeigned, unflagging, unremitting,
   unrestrained, unsleeping, unsparing, unwearied, urgent, vehement,
   vigorous, warm, warmhearted, white-hot, wholehearted, zealous