GOP Rep. Adam Kinzinger Uses Trump's Biggest Insult Against Him. Repeatedly.

Rep. Adam Kinzinger (R-Ill.) repeatedly jabbed Donald Trump with the one word the former president reportedly hates.

Kinzinger called him a “loser.”

Trump used the “L” word to describe Kinzinger and other critics in his own party in a recent news release. But the Illinois lawmaker was unfazed, instead offering Trump a blunt reminder of the record.

“I’ve never lost an election. He has,” Kinzinger said. “He’s the only loser in that mix, and we’re trying to grab onto him as if he’s somehow the ticket to the future, and he is instead obsessed with the fact that he lost again at something.”

Kinzinger, who crossed party lines to vote for impeaching Trump this year, said Trump should spend his post-presidency championing an issue he cares about, as other former presidents have done.

Trump has not.

“He’s down there obsessing about the fact that he’s a loser,” Kinzinger said. “I’m sorry you’re a loser. But you lost.”

Trump has frequently used the word “loser” in his insults and doesn’t like it when it’s used on him.

“The first thing he calls someone who has wronged him is a loser,” Jack O’Donnell, who ran a casino for Trump in the 1980s, told The New York Times last year. “That’s his main attack word. The worst thing in his world would be to be a loser. To avoid being called a loser, he will do or say anything.”

See Kinzinger’s full conversation with CNN’s Anderson Cooper below, in which he warns his own party against embracing Trump’s lies about the 2020 election:

This article originally appeared on HuffPost and has been updated.