The Collaborative International Dictionary of English v.0.48:

Howl \Howl\, v. i. [imp. & p. p. Howled; p. pr. & vb. n.
   Howling.] [OE. houlen, hulen; akin to D. huilen, MHG.
   hiulen, hiuweln, OHG. hiuwil[=o]n to exult, h?wo owl, Dan.
   hyle to howl.]
   1. To utter a loud, protracted, mournful sound or cry, as
      dogs and wolves often do.
      [1913 Webster]

            And dogs in corners set them down to howl.
                                                  --Drayton.
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            Methought a legion of foul fiends
            Environ'd me about, and howled in my ears. --Shak.
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   2. To utter a sound expressive of distress; to cry aloud and
      mournfully; to lament; to wail.
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            Howl ye, for the day of the Lord is at hand. --Is.
                                                  xiii. 6.
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   3. To make a noise resembling the cry of a wild beast.
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            Wild howled the wind.                 --Sir W.
                                                  Scott.
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   Howling monkey. (Zool.) See Howler, 2.

   Howling wilderness, a wild, desolate place inhabited only
      by wild beasts. --Deut. xxxii. 10.
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WordNet (r) 3.0 (2006):

howling
    adj 1: extraordinarily good or great ; used especially as
           intensifiers; "a fantastic trip to the Orient"; "the film
           was fantastic!"; "a howling success"; "a marvelous
           collection of rare books"; "had a rattling conversation
           about politics"; "a tremendous achievement" [syn:
           fantastic, grand, howling(a), marvelous,
           marvellous, rattling(a), terrific, tremendous,
           wonderful, wondrous]
    n 1: a long loud emotional utterance; "he gave a howl of pain";
         "howls of laughter"; "their howling had no effect" [syn:
         howl, howling, ululation]

Moby Thesaurus II by Grady Ward, 1.0:

143 Moby Thesaurus words for "howling":
   Jeremianic, abandoned, acute, amok, animal noise, argute, awful,
   bark, barking, bawling, bellowing, bemoaning, berserk, bewailing,
   birdcall, birdies, blatant, blooping, blurping, call, carried away,
   clang, complaining, creaky, cry, crying, deadly, delirious,
   demoniac, distortion, distracted, dreadful, ear-piercing, ecstatic,
   enraptured, faultfinding, fearful, feedback, feral, ferocious,
   fierce, flutter, fluttering, frantic, frenzied, fretful, frightful,
   fulminating, furious, grieving, grunt, haggard, hissing, hog-wild,
   horrible, howl, hum, hysterical, in a transport, in hysterics,
   intoxicated, keen, keening, lamentation, lamenting, lamentive,
   lowing, mad, madding, maniac, mating call, moanful, moaning,
   motorboating, mournful, mourning, mugient, note, orgasmic,
   orgiastic, peevish, penetrating, petulant, piercing, piping,
   plaintive, plangent, possessed, puling, querulous, rabid, raging,
   ramping, ranting, raving, ravished, reedy, roaring, rousing,
   rumble, running mad, scratching, screaky, screeching, screechy,
   sharp, shredding, shrieking, shrieky, shrill, sorrow, sorrowful,
   sorrowing, squeaking, squeaky, squeals, static, storming,
   stridulation, terrible, terrific, thin, thumping, transported,
   ululant, ululation, uncontrollable, violent, wailful, wailing,
   whacking, whimpering, whining, whiny, whistles, whistling, wild,
   wild-eyed, wild-looking, woodnote, woomping, wow, wowwows