The Collaborative International Dictionary of English v.0.48:

Fervid \Fer"vid\, a. [L. fervidus, fr. fervere. See Fervent.]
   1. Very hot; burning; boiling.
      [1913 Webster]

            The mounted sun
            Shot down direct his fervid rays.     --Milton.
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   2. Ardent; vehement; zealous.
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            The fervid wishes, holy fires.        --Parnell.
      -- Fer"vid*ly, adv. -- Fer"vid*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

fervidness
    n 1: feelings of great warmth and intensity; "he spoke with
         great ardor" [syn: ardor, ardour, fervor, fervour,
         fervency, fire, fervidness]