Fountain of Knowledge

I don't know, I myself think "killing" sounds harsher than "murder".. Maybe it's just me, but well, I used to hear lots of "killing" in movies and somehow relate it to some gruesome and gory acts, something... primal? While I usually relate "murder" to something more sophisticated, like all those detective movies... killings with consciousness and real motives...

But that aside, the connotation I can offer is probably... "homicide"? Or if you're referring to the verb form, perhaps "slay" or "execute" or "massacre"? Though the last word, in my opinion, is harsh as well...

Hope this helps.

~Cat-Claws.