The killing of a human being, committed by another. justifiable homicide. The killing of a human excused by the law as appropriate or necessary; for example, in self-defense. negligent homicide. The killing of another by an act of irresponsibility or lack of attention to duty, rather than by intentional act. horizontal privity vehicular homicide. The killing of another by operation of a motor vehicle; generally the driver's acts must be more than just negligent; for example, in a motor vehicl...