Trump made the remarks during a rally in Manchester, New Hampshire, just hours before the polls opened in the state's primary.
"You heard the other night at the debate, they asked Ted Cruz, serious question: “Well what do you think of waterboarding?” Is it okay? And honestly I thought he’d say absolutely and he didn’t," Trump told the audience.
After that a woman shouted a crude word.
"Okay you’re not allowed to say and I never expect to hear that again," Trump said in response. "I never expect to hear that from you again."
But then Trump repeated the woman's remarks.
"She said he's a [crude word] that's terrible," he said, before throwing his hands up.