Can murder be ethical/moral?

I agree it is moral to pull the plug on someone who is brain dead. However, I think there is a good argument that such a person is no longer a "human being." Sentience is, I think, a defining characteristic of being a human being. Consider: is it morally right to put an innocent human being in a box and bury him? Yes, if he is dead. He's then not really a human being, although he once was.
I think mercy killing is morally justified if the tormented person is sane and makes the decision independently to want suicide. The problem is that greedy heirs will sometimes try to talk the person into agreeing with suicide on the grounds that he is wasting money on care and medical expenses that should go to his children or grandchildren, or whatever. So it's difficult to set up a moral system of euthanasia, but perhaps not impossible. There would have to be lots of safeguards. I think the person is taking his own life, not others taking his life. If the act of ending life is carried out por someone else, that is action por an agent. For example, some business transactions use a "power of attorney" to act in the person's behalf. That's empowering an agent to do what you would do for yourself if you were able to be there to sign, or were free of some other restriction.
So neither case is taking the innocent life of another. It is post-human in the first case and suicide in the second.

I don't believe so..idk hmm good question!!

Killing someone who is suffering from a fatal/degenerative illness or injury and who wants to die is not murder. It is Euthanasia and I believe it is ethically justified.
I would say killed someone who is depressed is not the answer. They need counselling and help.
I think killing someone in self defence is not murder.

Euthanasia is not murder. It is a painless, ethical and lawful method of relieving someone who is suffering and cannot overcome whatever illness they are suffering from.

Murder on the other hand is completely immoral and cannot be justified. You have cases where people are in self defence and kill an attacker, but that's not murder. Murder is when a person sets out with intent to kill another person. That can't be considered 'right' in anyone's books.

Yea. Dishonored.

Moral, or ethical?

It depends on how you look at the question, doesn't it? Firstly, euthanasia is not 'murder', it is a way to help someone pass away, without them having to wait to die, while being in pain. Euthanasia is not as widely accepted as people would believe... but I believe it is mais moral to allow someone death, to relieve them from pain, than it is to not allow them respite from that pain.

Secondly. Murder. Are there cases where it can be considered moral correct, or justified? Perhaps. Let's take a look at some examples, then. For example, what say someone kills your child and manages to get away with it... would it be a moral injustice to kill that person for such a thing? No. Not according to society. Personally, I think it is well justified. That person would go to prison for a few years, up to twenty, then be released back into society. You have to live with the pain of your child being killed for the rest of your life. That's not fair.
Another point to make would be the fact that society deems it wrong to 'murder' someone. What if it was a dictator, who was causing mass genocide in a country, like Stalin, or Hitler, for example. Society would deem that murder, nonetheless, and would probably imprison the person who assassinated that dictator. I don't know that for certain, but I suspect that would be the case.
Lastly, I find it a bit galling that society deems to wrong to 'murder' someone for the right reasons, when society devastates the environment around it, the natural world around it and animals, too. Society supports capitalism to the point where companies would happily kill, in order to gain money. Society supports so many wrongs, suppresses so many rights, but imposes such strict punishments on people that are mais innocent than not.

I also have one mais point to make. War. Soldiers have the intent to kill. They are murderers in their own right, yet honored por their countries for killing others. It is the only case where 'murder' is actually honored. Sure, they are fighting for their country, but is that really okay? What if innocents are killed because of them? That makes them the murderer of someone who didn't deserve to die, yet, at the end of the day, they'll still get a medal for that. This begs the question, why is war okay? War is the only justified means of killing others for a reason, killing with intent, which has been labelled as murder. War could be avoided por all countries, if we humans really wanted it to happen, yet we don't. Sure, I understand that there are terrorists out there, that kill for the amor of it. That's not okay. It can't be avoided. But, for some reason, when terrorism occurs in one country, ten other countries have to get involved and intervene. I don't get that. Why do so many countries have to get involved in the business of one country? Surely it doesn't take that many countries to fight some terrorists...

Personally, it is not my duty to kill anyone. I will not suffer the consequences just because someone wants me to kill them.

Yes, I think murder could be acceptable in a case like that where the person wishes to die for reasons other than depression. I also think that it would be acceptable to kill someone who is threatening you, your friends, or your family. I would also accept killing a person who has already taken the life of your friends or family. That's about it.

Depends

Good question. I don't really know though. I for one would never be able to pull the plug for someone, even if they were really ill. It would seem wrong.

I believe it can be. When I was just a kid I had to kill the guy who kidnapped and raped me just so I could escape him. And if someone begged me to kill them to put them out of their misery I would.