The act of killing is the act of depriving someone of their life. I know there are controversies about the point that someone is alive, but for all intended purposes will side with the type of killing after someone is born. Killing someone is only ok in my opinion (Because I can only state opinion for this section) is if it is in self defence where you feel your own life is in danger of being deprived, or if you are a soldier in combat whose obligation is to be prepared to kill if need be. Which is pretty much the same as the first reason, but with more reason behind it.
It is only "wrong" because we are social animals. It is not beneficial for a society to kill its own (there are exceptions, of course). We do not want to be killed, so we get together with people who agree not to kill us in exchange for the same courtesy. As far as I can see, all human "morals" come from us being social creatures.
a: an injurious, unfair, or unjust act : action or conduct inflicting harm without due provocation or just cause
b: a violation or invasion of the legal rights of another
(Merriam Webster definition of wrong)
It's important to note that 'wrong' is a human word, and is therefore subject to our bias and perspective. If you ask the question, 'Why is killing bad for individuals and society,' the answer is extremely easy to come up with.
Why, you ask? Why is killing another human considered a horrific thing? Something to be frowned upon? The answer is simple.
We are each given our own life. Our own life to do with as we choose. Identifying yourself as a person with the right to take someone's life away from them is not right.
Now, I sense that many people are already mustering within their own minds: "Who does this person think she is? Deciding and confirming that killing is wrong. How does she know that her answer is the 'right' answer out of the thousands of people who have answered?"
I cannot confirm, as it would not be fair or just, that my particular feelings and/or answer to this person's question is the "right" belief. However, my personal common sense and morals tell me that letting yourself be the person to decide whether someone else lives or dies is essentially wrong. I am a believer in free will and the right that we are given as human beings to make our own choices, especially when the matter is life or death. Who are you to decide whether another person, whom you only know by their outward appearances and tendencies and the few personal things they may have chosen to share with you, should continue on living or die? With my collective experience and knowledge, I have a firm and unwavering belief that people must and should always be able to choose whether or not to continue on living for themselves.
Another person's life is not something that you get to decide.
Think about it. When you kill someone, who did you kill? You killed someone's father, someone's mother, someone's lover, someone's sister, someone's brother, someone's most treasured companion. You are taking the life of someone who means the world to someone else. What did they do to you? Not only did you kill someone, but even a few more lives. The future of that person, whether it be to have many children or not, will never happen. Think about all you have done in that context if not religiously