cold-blooded

cold-blooded
    adj 1: without compunction or human feeling; "in cold blood";
           "cold-blooded killing"; "insensate destruction" [syn:
           {cold}, {cold-blooded}, {inhuman}, {insensate}]
    2: having cold blood (in animals whose body temperature is not
       internally regulated) [ant: {warm-blooded}]
    

Cold-blooded \Cold"-blood`ed\, a.
   1. Having cold blood; -- said of fish or animals whose blood
      is but little warmer than the water or air about them.
      [1913 Webster]

   2. Deficient in sensibility or feeling; hard-hearted.
      [1913 Webster]

   3. Not thoroughbred; -- said of animals, as horses, which are
      derived from the common stock of a country.
      [1913 Webster]
    

30 Moby Thesaurus words for "cold-blooded":
      apathetic, barbaric, barbarous, brutal, callous, cool, cruel,
      dispassionate, heartless, imperturbable, indifferent, inhuman,
      insensitive, merciless, pitiless, poikilothermic, ruthless, savage,
      steely, stony, thick-skinned, uncaring, unemotional, unexcited,
      unfeeling, unimpassioned, unmoved, unresponsive, unsympathetic,
      vicious