Political graffiti in Hartford Connecticut. Peter Glass/ Alamy

When’s the last time you told a shameless fib? Did you get caught? Do you know why? Maybe you couldn’t stop your eyes from darting around, or your hands from fidgeting. Maybe your nose started growing rapidly, like Pinocchio’s. Or did your would-be targets point out a smoky smell, coming from the seat of your jeans? It’s an association as strong as a steel rivet: from schoolyard taunts to political cartoons to fact-checking websites, a true liar’s pants are always on fire.

As popular as the saying has become, though—and as satisfying as it is to chant or say—“liar, liar, pants on fire!” is not the most intuitive of phrases. Although people’s pants do sometimes catch on fire, this correlates more with carrying around accidentally explosive materials than it does with truthfulness. Meanwhile, the vast majority of liars make it through life unscathed by this particular fashion catastrophe. The mystery of the phrase’s origins is compounded by the fact that several of its more popularly reported etymologies are, in fact, lies.

The phrase was likely invented by schoolkids fighting. L. Stocks/Wellcome Collection/Public Domain

“‘Liar, liar’—without the ‘pants on fire’—has been around a long time,” says Barry Popik, a linguist who specializes in slang and proverbs. As early as the 1400s, people would call each other out using the phrase “liar, liar, lick-dish!,” the idea being—according to one proverb dictionary—that the accused will “lie as fast as a dog will lick a dish.” Popik dug into the complete phrase in June of 2010 for his etymology blog, The Big Apple, and found a collection of English naval ballads from 1840, featuring a short poem that seems to come from this lineage, and that links two of the phrase’s main aspects, lying and fire: “Liar, liar, lick spit / turn about the candlestick,” it reads. “What’s good for liar? Brimstone and fire.”

All of these, though, are missing that crucial pants element. The earliest full example Popik found was from the 1930s—specifically, the August 13, 1933, issue of the Sunday World-Herald. In an article titled “Fat Pat to Rassle Savage Because the Public Wants It,” a reporter wrote that fans had been clamoring to see “Fat” Pat McGill rassle Steve Savage, to the extent that the local wrestling promoter has been “deluged by letters, swamped by phone calls, and buried under an avalanche of telegrams.” This news is followed by a cheekily defensive parenthetical: “It is so, you liar, liar, pants on fire; there were several people who called up.”

A 1930s wrestling match, which likely featured some taunts. Library of Congress/LC-DIG-fsa-8a23144

The phrase is deployed casually, which suggests that it may already have been fairly well-known at that point. Popik also found a number of uses from the late 1930s and 1940s, most of them embedded in the classic playground poem, which also brings in some Pinocchio imagery: “Liar, liar / pants on fire / nose as long as a telephone wire!” But whatever genius child first came up with this taunt has been lost to the annals of time. “Unfortunately, we didn’t have Twitter back then,” Popik says. “If we had Twitter, I’d be able to pin this down to the exact day and exact hour.”

Amateur etymologists and pranksters have stepped in to fill the gap. A commenter on one popular etymology blog cited a story he read in a history book, about an 18th-century British merchant who was famously mendacious, and who once lit his pants on fire while loading his gun and smoking a cigar at the same time. (“It’s highly unlikely the saying is from the 1700s,” says Popik, who had never heard this story.) One Yahoo Answers member, known simply as Bryce, cited a Biblical verse featuring the line “‘Thy trousers, they burn with a fire as though from Heaven.” (This is, of course, not a real Biblical verse—Bryce made it up.)

The Bible features a burning bush, but not burning pants. Holman Bible/Public Domain

And then there is the poem “The Liar,” commonly attributed to William Blake, which begins in a familiar way:

“Deceiver, dissembler

Your trousers are alight

From what pole or gallows

Shall they dangle in the night?”

Further verses, which are worth reading, bring in an ill-fated horse, a “red devil of mendacity” who “grips your soul with such tenacity,” and another instant-classic couplet: “from what pit of foul deceit / are all these whoppers sprung?” Anyone who has read Blake’s best-known poem, “The Tyger,” will recognize the poem’s meter, rhyme scheme, and question-based structure.

Sorry everyone, William Blake did not invent this phrase. Thomas Phillips/Public Domain

But the poem itself is an imposter: it was written not by Blake in 1810, but by a gifted parodist sometime around 2010. It comes courtesy of the Uncyclopedia, a now-defunct website that billed itself as a “content-free encyclopedia,” and it has fooled a lot of people seeking high-minded ways to talk about lying, from investment bankers to ministers to social scientists. They’ve fallen for a classic trap: “Famous people—such as Mark Twain, Abraham Lincoln, Thomas Jefferson, and Winston Churchill—get famous quotes attributed to them,” Popik says. “Unfortunately, the bogus quotes are still around in the internet age… people are too lazy to search for a few seconds.”

Despite its lack of fascinating backstory or literary pedigree, though, “Liar, liar, pants on fire” has spent decades doing just fine on its own. “It’s a nice rhyme,” says Popik, when asked about its longevity. Plus, he adds, it’s perpetually relevant: “There are a lot of liars.” Make sure you’re not one of them: before you spread a linguistic origin story, take a second to do a little research. Otherwise, your own trousers might end up aflame.