The Collaborative International Dictionary of English v.0.48:

Savagery \Sav"age*ry\ (?; 277), n. [F. sauvagerie.]
   1. The state of being savage; savageness; savagism.
      [1913 Webster]

            A like work of primeval savagery.     --C. Kingsley.
      [1913 Webster]

   2. An act of cruelty; barbarity.
      [1913 Webster]

            The wildest savagery, the vilest stroke,
            That ever wall-eyed wrath or staring rage
            Presented to the tears of soft remorse. --Shak.
      [1913 Webster]

   3. Wild growth, as of plants. --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

savagery
    n 1: the property of being untamed and ferocious; "the coastline
         is littered with testaments to the savageness of the
         waters"; "a craving for barbaric splendor, for savagery and
         color and the throb of drums" [syn: savageness,
         savagery]
    2: the trait of extreme cruelty [syn: ferociousness,
       brutality, viciousness, savagery]
    3: a brutal barbarous savage act [syn: brutality, barbarity,
       barbarism, savagery]

Moby Thesaurus II by Grady Ward, 1.0:

81 Moby Thesaurus words for "savagery":
   Gothicism, Neanderthalism, acuteness, age of ignorance, animality,
   atrociousness, atrocity, barbarism, barbarity, barbarousness,
   beastliness, benightedness, benightment, bestiality, bloodiness,
   bloodlust, bloodthirst, bloodthirstiness, bloody-mindedness,
   brutality, brutalness, brutishness, cannibalism, cruelness,
   cruelty, dark, dark age, darkness, destructiveness, extremity,
   ferociousness, ferocity, fiendishness, fierceness, force,
   furiousness, harshness, heathenism, ill breeding, impetuosity,
   impoliteness, incivility, inclemency, inhumaneness, inhumanity,
   intensity, malignity, mercilessness, mindlessness, murderousness,
   paganism, philistinism, pitilessness, rigor, roughness,
   ruthlessness, sadism, sadistic cruelty, sanguineousness, savagism,
   severity, sharpness, terrorism, troglodytism, truculence,
   uncivilizedness, uncouthness, uncultivatedness, uncultivation,
   unculturedness, unenlightenment, ungentleness, unrefinement,
   vandalism, vehemence, venom, viciousness, violence, virulence,
   wanton cruelty, wildness