Subtitle: Even more cruelty.
Spite showed up in the fourteenth century as a short version of the word despit—or, you know, despite. Despite actually showed up around the same time, meaning defiance or “an act designed to humiliate someone”, from the Old French despit and classical Latin despectus, which means overlook, as in, look down on. The de- means down and the rest is from spicere, to look. So, to look down on. Which got the down part removed.
Callous showed up in the fifteenth century meaning hardened in the physical sense, much like a callus is hardened skin. It didn’t actually take on the figurative meaning until the late seventeenth century! Both callous and callus are from the classical Latin callosus, which means thick-skinned. Not really anything surprising about this one, either.
Vicious showed up in the late fourteenth century meaning unwholesome or corrupting, or, in the case of text, erroneous. Yeah, it didn’t mean savage until the early eighteenth century. It comes from the Anglo French vicious and Old French vicios, and before that the classical Latin vitiosus, vicious, faulty, or corrupt. That corrupt thing is important here, as vitiosus comes from vitium, fault, which just so happens to be the origin word for vice.
Finally today, harsh, which is ironically the least harsh of these words. It showed up in the sixteenth century where it actually originally had to do with texture, and that texture was hairy. Seriously! It didn’t mean what we know it as until the end of the sixteenth century, and no idea how it got from hairy to there. It’s thought to come from the Middle English harske, rough or coarse, which is Scandinavian in origin. That word is related to the Middle Low German harsch, rough or raw, and might be from the Proto Indo European root kars-, to scrape, scratch, or rub. Well, that makes more sense with harshness than it does with hairiness.