We’re looking at waste plus a special bonus of the word waist because they sound alike and that bothers me.
Waste showed up in the early thirteenth century, both as a verb which meant to ravage or ruin and a noun that meant desolation. Both words are from Anglo French and Old North French, with the nouns version being wast and the verb waster because French at least differentiates verbs and nouns. Both words can be traced to the classical Latin vastare, to devastate. You might be thinking that’s the origin word for vast. And it is! But it’s also related to the origin word for vain, of all things (because the vain origin word means empty, like something vast or wastelands). But that’s not the end of the weirdness. There’s an Old English version of the word, westan, which is Germanic and origin. That’s probably related to vastare, but it’s not where we Modern English speakers get our waste from. That would make too much sense.
Waist on the other hand showed up in the late fourteenth century meaning both the middle of the body and a garment that you wore on your waist. It’s thought to come from the Old English waest, growth, based on the thought that a waist is “where the body grows”. Look, I’m just telling you what I read. Waest comes from the Proto Germanic wahs-tu-, which is related to wahsan, the origin word for wax—not candle wax, like the moon waxes. Also, wahs-tu- comes from the Proto Indo European wegs-, which is from aug-, to increase. The origin word for augment.
What the hell universe am I in?
Tony Jebson’s page on the Origins of Old EnglishDictionary.com