When the Kansas City Chiefs defeated the Cincinnati Bengals in the AFC championship game last Sunday, Chiefs tight end Travis Kelce needled Cincinnati’s mayor, Aftab Pureval, for having mocked the Chiefs in the lead-up to the game. “Hey, I’ve got some wise words for that Cincinnati mayor,” Mr. Kelce said during the trophy celebration. “Know your role and shut your mouth, you jabroni!”

The mayor, for his part, was a good sport about it all, tweeting, “Yeah. Deserved that.” And as he told the Cincinnati Enquirer, he knew exactly what it meant to be called a “jabroni,” because he had grown up watching professional wrestling. In wrestling parlance, a “jabroni” is a fool or a loser.

The wrestler most associated with the “jabroni” insult is Dwayne “The Rock” Johnson, who frequently slung the word against his WWE rivals as he became a fan favorite starting in the late 1990s. (“Know your role and shut your mouth” was also part of The Rock’s pugnacious ringside patter.)

Mr. Johnson, however, is quick to point out that he didn’t coin the word “jabroni.” He gives credit to wrestling great Khosrow Ali Vaziri, better known as The Iron Sheik. As he explained in a 2015 interview with Esquire, “The Iron Sheik was famous for saying the word constantly backstage. Jabroni, jabroni, jabroni. Around 1998, I thought, why can’t I say it on TV? So I started saying it publicly, but The Iron Sheik was known for it.”

As for the word’s origins, Mr. Johnson surmised that it was “carny” talk, since wrestling used to be a featured attraction at carnivals. In fact, “jabroni” has much older roots as an insult for a contemptible or worthless person, going back more than a century in American slang.

The earliest known incarnation of the word was “jiboney” or “giboney,” first appearing in the writings of Jack “Con” Conway in the magazine Variety. Written in the style of letters to friends, Conway’s columns were packed with Jazz Age slang—he is credited with popularizing such words as “scram,” “bimbo,” “palooka,” and “baloney.”