I think the term "reet" originated from the "zoot suit" generation/fad. I've never seen an explanation of how the oddly-fitting "zoot suit" go its name but it almost seems to have been one of those things where someone didn't know how to name it so he just came up with a catchy rhyme. Of course men's clothing in those days all had pleats in various places to help shape them so a really "cool" outfit would be a "zoot suit with a reet pleat". Now before anyone assumes I'm so old that I was part of that fad, let me hasten to add that all I know and speculate on here came from old cartoons and shows on tv.

An old phrase I heard so much as a kid went "He thought like Lit" meaning someone thought one thing but was proven wrong. When I finally got so curious that I couldn't stand not knowing who/what "Lit" was and asked, I was told that Lit was some fellow who "thought he farted but he shit." So Lit was just a rhyme for shit. Once the entire saying was known, adults could use the first part in front of kids w/o having to say a word that they'd rather the kids not start using.

SC