pitiless

from WordNet (r) 3.0 (2006)

pitiless
    adj 1: without mercy or pity; "an act of ruthless ferocity"; "a
           monster of remorseless cruelty" [syn: {pitiless},
           {remorseless}, {ruthless}, {unpitying}]
    2: deficient in humane and kindly feelings [syn: {pitiless},
       {unkind}]

from The Collaborative International Dictionary of English v.0.48

Pitiless \Pit"i*less\, a.
   1. Destitute of pity; hard-hearted; merciless; as, a
      pitilessmaster; pitiless elements.
      [1913 Webster]

   2. Exciting no pity; as, a pitiless condition.
      [1913 Webster] -- {Pit"i*less*ly}, adv. --
      {Pit"i*less*ness}, n.
      [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

57 Moby Thesaurus words for "pitiless":
      atrocious, barbaric, barbarous, bestial, bloody, bowelless, brutal,
      brutish, coldhearted, cruel, cutthroat, dog-eat-dog, feral, ferine,
      ferocious, fierce, flinty, hard, hardhearted, harsh, heartless,
      inclement, inexorable, inhuman, inhumane, ironhearted, kill-crazy,
      malign, malignant, marblehearted, merciless, murderous,
      noncivilized, relentless, remorseless, ruthless, sanguinary,
      savage, stony, tameless, uncivilized, uncompassionate,
      uncompassioned, unfeeling, unforgiving, ungentle, unmerciful,
      unpitiful, unpitying, unremorseful, unsympathetic, unsympathizing,
      untamed, unyielding, vicious, wild, without mercy