poisoner (n.)

• apache
• assassin
• assassinator
• bravo
• butcher
• cannibal
• cutthroat
• desperado
• eradicator
• executioner
• exterminator
• garroter
• gorilla
• gun
• gunman
• homicide
• killer
• man-eater
• manslayer
• matador
• murderer
• pesticide
• poison
• slaughterer
• slayer
• strangler
• thug
• torpedo