True, the Latin verb is occido, from the verb "cado," which literally means to "cut off or to fall away from." The word "cadaver" is that which has been cut away from the soul. But the Douay translation was the first English translation, 1635, and there were clearly two words in English, "kill" and "murder," and the Fathers at the college of Douay in France chose the word "murder" when they rendered the English New Testament. I do not think it a small thing for some English bishop to come along two hundred years later and decide to swap out the word "murder" with the word "kill."