murderer

from WordNet (r) 3.0 (2006)
murderer
    n 1: a criminal who commits homicide (who performs the unlawful
         premeditated killing of another human being) [syn:
         {murderer}, {liquidator}, {manslayer}]
    
from The Collaborative International Dictionary of English v.0.48
Murderer \Mur"der*er\ (m[^u]r"d[~e]r*[~e]r), n.
   1. One guilty of murder; a person who, in possession of his
      reason, unlawfully kills a human being with premeditated
      malice.
      [1913 Webster]

   2. A small cannon, formerly used for clearing a ship's decks
      of boarders; -- called also {murdering piece}. [Obs.]
      [1913 Webster]
    
from Moby Thesaurus II by Grady Ward, 1.0
42 Moby Thesaurus words for "murderer":
      Cain, apache, assassin, assassinator, bloodletter, bloodshedder,
      bravo, burker, butcher, button man, cannibal, cutthroat, desperado,
      eradicator, executioner, exterminator, garroter, gorilla, gun,
      gunman, gunsel, hatchet man, head-hunter, hit man,
      homicidal maniac, homicide, killer, liquidator, man-eater,
      man-killer, manslayer, massacrer, matador, pesticide, poison,
      poisoner, slaughterer, slayer, strangler, thug, torpedo,
      trigger man

    

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