The Collaborative International Dictionary of English v.0.48:

Truculence \Tru"cu*lence\, Truculency \Tru"cu*len*cy\, n. [L.
   truculentia.]
   The quality or state of being truculent; savageness of
   manners; ferociousness.
   [1913 Webster]

WordNet (r) 3.0 (2006):

truculence
    n 1: obstreperous and defiant aggressiveness [syn: truculence,
         truculency]

Moby Thesaurus II by Grady Ward, 1.0:

74 Moby Thesaurus words for "truculence":
   abruptness, aggression, aggressiveness, animality, antagonism,
   atrociousness, barbarity, barbarousness, bearishness, beastliness,
   bellicism, bellicosity, belligerence, belligerency, bestiality,
   bloodiness, bloodlust, bloodthirst, bloodthirstiness,
   bloody-mindedness, bluntness, boorishness, brashness, brusqueness,
   brusquerie, brutality, brutalness, brutishness, cannibalism,
   chauvinism, churlishness, combativeness, contentiousness,
   cruelness, cruelty, crustiness, curtness, ferociousness, ferocity,
   fiendishness, fierceness, fight, gruffness, harshness, hostility,
   inhumaneness, inhumanity, jingoism, martialism, militancy,
   militarism, nastiness, pugnaciousness, pugnacity, quarrelsomeness,
   roughness, ruthlessness, saber rattling, sadism, sadistic cruelty,
   sanguineousness, savagery, severity, sharpness, shortness,
   surliness, unfriendliness, unpeacefulness, vandalism, viciousness,
   violence, wanton cruelty, warmongering, warpath