Thing Not To Be Today: thrawn.

 This is a word of Scotland and Northern England.

It has two meanings - well, two and a half, really - because can mean crooked/twisted, or stubborn, or perverse.

Because to be stubborn and to be perverse aren't entirely the same thing. It is possible to be stubborn about some useful endeavor, like writing a book or training a dog. To be perverse, the book would have to be a memoir of cutting your toenails; or you'd have to be stubbornly trying to train earwigs.

The difference between crookedness and perversity is pretty shaded, too, but they're both to do with not going at things straight.

It's interesting that the same word can do service, in the North of Britain, for all three.

I wonder if anyone's done a Venn Diagram of the use of the word?

Thing Not To Be Today: thrawn. This is a variation on the word thrown, from the Old English thrāwan, to twist about or to throw.