Chuck Todd, moderator of “Meet the Press,” on set in Washington. (William B. Plowman/NBC via AP)

President Trump, ever in favor of a memorable moniker for his Lyin’ or Crooked or Little targets of ire, has a puzzling nickname for the host of NBC’s “Meet the Press”: “Sleepy Eyes Chuck Todd.”

Trump has been referring to Todd’s eyes on Twitter since 2012 — most recently, he used the phrase Sunday when reacting to Todd’s televised comments on North Korea — but he has never explained just what he means about Todd’s eyes.

This week, some Twitter users posited a troubling explanation: “Sleepy eyes” might be an anti-Semitic slur that Trump uses to target Todd, who is Jewish. Others said it is unlikely Trump or any of his advisers know about the slur, which is uncommon.

In Nazi Germany, propagandists listed physical characteristics that differentiated Jews from Aryans. While some characteristics were far more often mentioned, such as large noses and curly hair, drooping or “sleepy” eyes occasionally made the list.

For example, according to the German Propaganda Archive at Calvin College, Nazi politician Julius Streicher (the publisher of the notoriously anti-Semitic newspaper Der Stürmer) wrote a children’s book listing a litany of supposedly Jewish traits, including the drooping eyes stereotype.

White supremacists today have carried forward many of those Nazi stereotypes, including the reference to “sleepy eyes.” Internet users searching neo-Nazi websites for traits of Jews might come across the reference. For example, on the website Gentile Nation — which bills itself as a Satanist website and includes a page titled “A True Hero: Hitler” — a 26-page document full of photos, of both Jewish celebrities and ordinary Jewish children pulled from Jewish organizations’ websites, teaches readers “How to Identify a Jew.” The document says that one of three types of eyes common to Jews is “the sleepy and sometimes bulging eyes, the sad sack eyes,” illustrated with photographs of “the Jewish ‘sleepy-eye.’ ”

But did Trump know about the history of the term “sleepy eyes” when he started applying it to a Jewish NBC reporter more than five years ago?

That’s not clear. Before this month, a search of Twitter history shows that almost no one raised the question of whether “sleepy eyes” was a reference to Todd’s religion when Trump tweeted the phrase many times before.

But then, on Sunday, Todd talked about North Korea on television. Trump tweeted in response. And the question of whether “sleepy eyes” came from neo-Nazis came raging to life on Twitter, thanks largely to a thread by a user called @Stonekettle which quickly started trending.

Now, scores of Twitter users are asking the president whether he knew the history of the term when he started applying it to Todd. Trump has not yet responded to the inquiries, and a White House spokesman did not respond to The Post’s questions before publication.

For his own part, Todd told The Post he didn’t think of the odd nickname as anti-Semitic. “I’ve never taken it that way. If it is a slur, I’ve never heard of it,” Todd said.

Peter Kenez, an emeritus professor at the University of California at Santa Cruz who survived the Holocaust and went on to become a historian of the atrocities he witnessed, wrote about the “sleepy eyes” stereotype in one of his books. However, he thinks it is very unlikely that Trump knows about it, or that he picked up the term from one of his advisers.

Instead, Kenez said, it is probably just a coincidence that Trump uses the same nickname for Todd.

“I doubt that Trump knows what he’s talking about. . . . [‘Sleepy eyes’] was hardly a major feature of Nazi propaganda. It was not something that every German had to know,” Kenez said. Other stereotypes were far more common in Nazi Germany, he said. “I think it is too obscure. Our president has to have it to think up an adjective for everyone that he says something bad about. I suppose nothing else came to him.”