“I’m talking about — hey, by the way she says things about me that are horrible,” Mr. Trump said. “As an example, the single greatest asset that I have according to those that know me is my temperament. But she came up with this Madison Avenue line, ‘Oh, let’s talk about his temperament.’ It’s the single greatest asset I have, my temperament.”

Mr. Trump has a history of making provocative comments about women and their looks, and his latest line of attack is unlikely to help him close the sizable gender gap between him and Mrs. Clinton, the Democratic nominee, who would be the nation’s first female president if elected in November.

In a new CNN/ORC poll, Mrs. Clinton leads Mr. Trump 52 percent to 38 percent among likely female voters. And among all registered female voters, the same poll found that 62 percent said Mrs. Clinton had the better temperament to serve effectively as president, while only 29 favored Mr. Trump’s temperament.

Mrs. Clinton’s campaign was quick to respond to the Republican nominee’s latest provocation.

“This isn’t the first time Donald Trump has had a problem looking at someone different from himself and actually seeing them,” said Christina Reynolds, deputy communications director for the Clinton campaign, citing his criticism of a Mexican-American judge and the mother of a slain Muslim American soldier. “So it’s not surprising that Donald Trump doesn’t think Hillary Clinton looks presidential. This cycle, voters know all too well what’s not presidential: Donald Trump and his narrow views and divisive rhetoric.”

Emily’s List, a group that works to elect Democratic women who support abortion rights, also assailed Mr. Trump, saying he was playing the “gender card” and “just blew the dog whistle so hard, our ears are ringing.”