A couple of clarifications, though: I did mean unsafe rust, not the safe subset. No need to get rude!
Second of all, I am of course not under the illusion that Odin prevents use-after-free (and thus, technically, it does allow UB I guess). I just don't think Bill is either. So clearly he doesn't mean UB by the same definition as you do.
_My_ use of UB has always been in the context of what a compiler will do during optimization, and the discussion I've seen in the context of C compilers is that they perform optimizations that remove code or change code in surprising ways because the way the code was written technically resulted in UB. But I'm neither a spec writer or a compiler author, so I don't really care that much about the actual definition of the term.
Anyway, best of luck in convincing Bill to use the term correctly as well! I won't mention UB when talking about the benefits of Odin in the future. :)