Killing is justified (ie...war & self-defense) and murder is not.

Kill is an act to cause deadth, terminated or ended. Murder is the same as kill, an act to cause deadth, it is more often use in law. " Murder", the element of law define murder: the killing must be planned with intend. The differences: Kill - an act to cause deadth, terminated or ended Murder - an act to cause deadth, terminated or ended and such act must be performed with plan and intend.

I think killing is just an in general, someone or something cause the end of another person's life, whether there was intent or reason. Whereas a murder is to kill with an intent, the person or animal meant to kill another person or animal, it was not an accident. Murder is killing, but killing is not necessarily murder, you see what I mean?

i disagree with the first comment. killing is not necessarly justified. a sentence like "the murderer killed five people" is absolutely correct. the verb "to kill" is the neutral form to express the act of "taking away one's or something's life". A hunter might kill a deer, just as a predator might kill its prey. Many people are killed in war. Somebody was killed in a car accident. A murderer might kill without remorse. The verb "to murder" on the other hand DOES have a moralistic meaning to it. "to murder" is to kill unjustly and with a selfish motivation. That's why many environmental activists call the killing of animals for the selfish purpose of eating their meat a murder.

To kill something is to end its life in a positive or negative way/reason. For example you can kill an animal to end its suffering. Or you could kill an animal for sport or because it is a nuisance. To murder is the same as To kill but you can never murder something in a nice way. Murder is allways seen as negative/bad. Hope that made some sense to you :S