He's just going to call her "lyin'" or "crooked" or something like that, so she might as well call him what he is...a criminal.
It's that kind of tit-for-tat that you wouldn't get from Joe Biden, who was worried about looking polite and respectable. It just wound up making him look weak.
I think the most streamlined nickname the lab-coat wearing neurons in his swollen, cancerous amygdala could come up with is "laffin'" and he had to fucking explain to the sheep he's trying to herd to he wanted it spelled.