"I don't get it," he said.
Mrs. Molloy straightened herself militantly in her chair. Of all masculine defects, she liked slowness of wit least; and she had never been a great admirer of Mr. Twist.
"You poor, nut-headed swozzie," she said with heat. What don't you get? It's simple enough, isn't it?
(from Money For Nothing, by Sir Pelham Wodehouse)
Nut-headed swozzie? Now there is a new one to me. I'll have to remember that one. Might or might not want to use it, depending on what it means in the ever-changing world of slang.