Somebody ... who has never shown any regard for workers, has never fought on behalf of social justice issues or making sure that poor kids are getting a decent shot at life or have health care," does not meet the definition, Obama said.
"They don't suddenly become a populist because they say something controversial in order to win votes. That's not the measure of populism. That's nativism, or xenophobia. Or worse. Or it's just cynicism," he said.
Trump won enough grassroots support among Republicans to make him the party's presumptive presidential nominee with a pledge to ban Muslims temporarily from entering the United States and to build a wall on the U.S. border with Mexico, and a series of other inflammatory remarks.
Obama has sharply criticized Trump for such rhetoric.
He plans to campaign with former Secretary of State Hillary Clinton, the presumptive Democratic presidential nominee, next week. The president's latest criticism of Trump could foreshadow Obama's strategy to help Clinton on the campaign trail.