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The Debunker: Is the "F Word" an Acronym for "For Unlawful Carnal Knowledge"?

by Ken Jennings

October is Crime Prevention Month, says the National Crime Prevention Council, and would the nonprofit that brought you McGruff the Crime Dog lie to you about crime prevention? In honor of the occasion, we've decided to shine the hard light of truth on the underbelly of the criminal underworld. As a Jeopardy! superhero, Ken Jennings doesn't fight crime—just misinformation about crime. He'll be here all month debunking felonious falsehoods and misdemeanor myths.

The Debunker: Is the "F Word" an Acronym for "For Unlawful Carnal Knowledge"?

Because its history often went unwritten for reasons of propriety, the notorious "f-word" has left itself open to all kinds of crazy folk etymologies. In two common versions, the word is actually an acronym. Sometimes the word is said to come from a sign advertising that a newlywed couple's marriage in olden times had been approved by the crown: "Fornication Under Consent of the King." (Presumably when a woman sat on the throne, the word was spelled "fucq.") In another version, prisoners locked in the stocks for sexual shenanigans were placed under a sign that read "For Unlawful Carnal Knowledge." Van Halen was so charmed by the transgressive power of this last acronym that they named a 1991 album and tour after it. Those naughty boys!

The Debunker

There are multiple problems with those explanations, chief among them the fact that forming words from acronyms wasn't really a thing before World War II—the word "acronym" was only coined in 1943, to refer to the new vogue for phonetically pronouncing abbreviations like snafu, radar, and WAC. There's also the fact that "fornication" doesn't really make sense in this context (married couples, by definition, cannot fornicate) and prisoners serving crimes were never places under signs with the word "for." The sign in such a case, if any, would have said something like "Adultery."

The f-word is first attested in written English in 1310, when court records mention an arrest warrant for a certain "Roger Fuckebythenavele." (If you think that was not an insult and Roger merely had a very unfortunate family name, then the real first usage is in a late 15th-century poem. In either case, that's centuries before acronyms caught on in English.) Our English word has cognates in German ("ficken," to copulate) and Dutch ("fokken," to breed) as well as Scandinavian dialects, and may even derive from Latin verbs that pre-date its Germanic usage. It's old af, y'all.

Quick Quiz: What 1960s folk-rocker made his movie debut in the Mike Nichols movies Catch-22 and Carnal Knowledge?

Ken Jennings is the author of eleven books, most recently his Junior Genius Guides, Because I Said So!, and Maphead. He's also the proud owner of an underwhelming Bag o' Crap. Follow him at or on Twitter as @KenJennings.