The Collaborative International Dictionary of English v.0.48:

Feral \Fe"ral\, a. [L. feralis, belonging to the dead.]
   Funereal; deadly; fatal; dangerous. [R.] "Feral accidents."
   --Burton.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

feral \fe"ral\, a. [L. ferus. See Fierce.] (Bot. & Zool.)
   Wild; untamed; ferine; not domesticated; -- said of beasts,
   birds, and plants.
   [1913 Webster]

WordNet (r) 3.0 (2006):

feral
    adj 1: wild and menacing; "a pack of feral dogs" [syn: feral,
           ferine, savage]

Moby Thesaurus II by Grady Ward, 1.0:

130 Moby Thesaurus words for "feral":
   Draconian, Tartarean, abandoned, amok, animal, anthropophagous,
   atrocious, baneful, barbaric, barbarous, beastly, bellowing,
   berserk, bestial, bloodthirsty, bloody, bloody-minded, brutal,
   brutalized, brute, brutish, cannibalistic, carried away, cinerary,
   cruel, cruel-hearted, deadly, death-bringing, deathful, deathly,
   delirious, demoniac, demoniacal, destructive, devilish, diabolic,
   dirgelike, dismal, distracted, ecstatic, enraptured, epitaphic,
   exequial, fatal, fell, ferine, ferocious, fiendish, fiendlike,
   fierce, frantic, frenzied, fulminating, funebrial, funebrious,
   funebrous, funeral, funerary, funereal, furious, haggard, hellish,
   hog-wild, howling, hysterical, in a transport, in hysterics,
   infernal, inhuman, inhumane, internecine, intoxicated, kill-crazy,
   killing, lethal, mad, madding, malign, malignant, maniac,
   merciless, mortal, mortuary, mournful, murderous, necrological,
   noncivilized, obituary, obsequial, orgasmic, orgiastic, pernicious,
   pitiless, possessed, rabid, raging, ramping, ranting, raving,
   ravished, roaring, running mad, ruthless, sadistic, sanguinary,
   sanguineous, satanic, savage, sepulchral, sharkish, slavering,
   storming, subhuman, swinish, tameless, transported, truculent,
   unchristian, uncivilized, uncontrollable, ungentle, unhuman,
   untamed, vicious, violent, virulent, wild, wild-eyed, wild-looking,
   wolfish