Characters
I've got a writ for you, rat. It's a rat writ writ for a rat.
— Rooster Cogburn ‧ True Grit

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker addresses a rat and announces a writ ready for the target, then piles up the words in a tongue-twisting phrase: a rat writ writ for a rat. The legal threat is delivered with insulting relish, using repetition to make the label stick.
Context reviewed