I did “pretty” words once, so I might as well do these.
Ugly showed up in the mid thirteenth century as uglike, which is awesome to say, I don’t know why we changed it. It’s Scandinavian in origin, related to words like the Old Norse uggligr (dreadful) and uggr (fear). The suffix part is from -ly, which means “like” and is a part of a lot of words.
Hideous showed up in the fourteenth century from the Anglo French hidous, and Old French hideus, which is from an older version of the word, hisdos. Once upon a time it was thought to be Latin in origin, but they no longer think that. Now they’re leaning towards Germanic, although they can’t actually say from where.
Gross actually has a few different meanings: a dozen dozen, amount earned, and also large. They’re actually all from the same place, and that includes the one we use for something nasty. In addition to the previous definitions, when it showed up in the mid fourteenth century it also meant course, plain, or simple, and from there it morphed to not sensitive, dull, or stupid, then course in a moral sense, then glaring, flagrant, or monstrous. Then in 1958, people started using it as slang. The word comes from the Old French gros, big, thick, fat, course, rude, etc., and before that, it was the Late Latin grossus (thick, course). And that’s all we know, because it doesn’t exist at all in classical Latin.
Nasty showed up in the late fourteenth century as nasti, and why does the I at the end make it look cute? It’s another one of uncertain origin, although some think it’s from Old Norse. Others think it might be from the Old French nastre, which means things like miserly and malicious, so maybe.
Vulgar showed up in the late fourteenth century from the classical Latin vulgaris/volgaris, common, from vulgus, common people. Vulgus can be traced to the Proto Indo European root wel-. So. Goes to show what everyone thinks about things that are “common”.
Finally today, disgust showed up in the sixteenth century from the Middle French desgoust, distaste, from desgouster, have a distaste for. The prefix dis- means opposite of, while gouster means taste, coming from the classical Latin gustare, to taste. If something disgusts you, you have the opposite of taste for it.