But Trump, who has endorsed Romney and has been campaigning on his behalf, objected to that premise.
"He's a hack. How he can say that is just incredible. I really think the Republicans, in the form of Mitt Romney, have a great chance to win the White House," Trump said.
Earlier in the discussion, Trump said he was supporting the former governor because he believed he was the only GOP candidate who could win against Obama.
"He's going to beat President Obama, and nobody else in the group will. I'm saying he's a good man who really gets it," Trump said.
It was not the first time Trump and Will have exchanged words. Will argued last year that the GOP should seek to prevent "entrepreneurial charlatans" like Trump from involvement in the election process. That drew a sharp rebuke from Trump at the time.