Yes this might be a statement so obvious it seems like it need not be said, but somehow a concerning amount of people seem to still think murder is a swell idea.
So where do we start, first off a definition will do us good...
Murder: intentionally killing people.
This is a pretty simple definition, it leaves out manslaughter (accidentally killing people) and killing not related to people.
Now we ran into our first hurdle with stopping murder, which is simply defining it and applying that definition equally. See unlike terms like "terrorist" whose definition always seems to get skewed to "people I don't like(usually with oil)" murder is too easy to understand for even the daftest of people to be fooled by wordplay.
However there are still a large amount of people who like to try and apply it selectively...