"That's not a birther thing," Stewart told David Axelrod during a live taping of "The Axe Files" podcast. "I'm not a constitutional scholar so I can't necessarily say, but are you eligible to run if you are a man-baby or a baby man?"
The former "Daily Show" host added:
"I'm not here to be politically incorrect, if they're referred to as man-baby Americans, but he is a man-baby. He has the physical countenance of a man and a baby's temperament and hands.
During the interview, Stewart referred to the pair's long-running feud, when Trump was a frequent target on "The Daily Show" and the real estate mogul countered by referring to Stewart by his birth name, Jonathan Leibowitz, on Twitter.
"So we tweeted back to him Donald Trump's real name," Stewart said. "Which I don't know if you know this, but it's 'Fuckface von Clownstick.'"
Stewart then returned to the topic of qualifications.
"I don't know that a man-baby can be president," Stewart said. "Character is destiny, and he is the most thin-skinned individual."
The clip was filmed before an audience at the University of Chicago Institute of Politics, which co-produced the podcast with CNN. Stewart also offered some advice for the students in the room who planned to get involved in politics.
"Get into it," he encouraged. "And don't get it on you."
See the full interview in the video above.