Origin of the "F" word

The American Heritage® Dictionary of the English Language: Fourth Edition. 2000. fuck PRONUNCIATION: fk VERB: Inflected forms: fucked, fuck·ing, fucks TRANSITIVE VERB: 1. Vulgar Slang To have sexual intercourse with. 2. To take advantage of, betray, or cheat; victimize. 3. Used in the imperative as a signal of angry dismissal. INTRANSITIVE VERB: 1. To engage in sexual intercourse. 2. To act wastefully or foolishly. 3. To interfere; meddle. Often used with with. NOUN: 1. An act of sexual intercourse. 2. A partner in sexual intercourse. 3. A despised person. 4. Used as an intensive: What the fuck did you do that for? INTERJECTION: Used to express extreme displeasure. PHRASAL VERBS: fuck off 1. Used in the imperative as a signal of angry dismissal. 2. To spend time idly. 3. To masturbate. fuck over To treat unfairly; take advantage of. fuck up 1. To make a mistake; bungle something. 2. To act carelessly, foolishly, or incorrectly. 3. To cause to be intoxicated. ETYMOLOGY: Middle English, attested in pseudo-Latin fuccant, (they) fuck, deciphered from gxddbov. WORD HISTORY: The obscenity fuck is a very old word and has been considered shocking from the first, though it is seen in print much more often now than in the past. Its first known occurrence, in code because of its unacceptability, is in a poem composed in a mixture of Latin and English sometime before 1500. The poem, which satirizes the Carmelite friars of Cambridge, England, takes its title, “Flen flyys,” from the first words of its opening line, “Flen, flyys, and freris,” that is, “fleas, flies, and friars.” The line that contains fuck reads “Non sunt in coeli, quia gxddbov xxkxzt pg ifmk.” The Latin words “Non sunt in coeli, quia,” mean “they [the friars] are not in heaven, since.” The code “gxddbov xxkxzt pg ifmk” is easily broken by simply substituting the preceding letter in the alphabet, keeping in mind differences in the alphabet and in spelling between then and now: i was then used for both i and j; v was used for both u and v; and vv was used for w. This yields “fvccant [a fake Latin form] vvivys of heli.” The whole thus reads in translation: “They are not in heaven because they fuck wives of Ely [a town near Cambridge].” And some people thought the word was used as follows.
Variant #1 Email example contributed by T. McInnis, 22 March 2001:
In ancient England a person could not have sex unless you had consent of the King (unless you were in the Royal Family). When anyone wanted to have a baby, they got consent of the King, the King gave them a placard that they hung on their door while they were having sex. The placard had F.*.*.*. (Fornication Under Consent of the King) on it. Now you know where that came from.

Variant #2 From a Usenet posting, 1 November 1990:
The word fuck comes from colonial times, when someone would be punished for 'prostitution' It was an acronym for the words
'For Unlawful Carnal Knowledge'FUCK was written on the stocks that held these criminals because For Unlawful Carnal Knowledge was too long to go on the stocks.

Variant #3 From a Usenet posting, 12 October 1990:
I always heard that "F.U.C.K." originated in the 1800's in London, when they used to charge prostitutes "For Unlawful Carnal Knowledge". So officer got sick and tired of writing those, um, lessee, 26 characters, not including spaces, so it got abbreviated FUCK and stuck.