It turns out that the f-word holds a long pedigree in judicial opinion-writing. John Baker sent in an 1846 Missouri opinion reputed to contain the first judicial mention of the word.
In Edgar v. McCutchen, McCutchen sued Edgar for slander. The slanderous allegation was, according to the court, “carnal knowledge of a mare, and the word ‘f**k’ [asterisks added; court used unabridged version] was used to convey the imputation.” After the plaintiff received a verdict, the defendant made a motion to arrest the judgment “for the reason that the word used to convey the slander, was unknown to the English language.”
If only that were true. The court disagreed and affirmed the plaintiff’s judgment.
Follow up: Kevin McDowell wrote to confirm that:
It appears to be true that Edgar v. McCutcheon (1846) is the first case to discuss the “F” word. The Indiana Supreme Court relied on the case in Linke v. Kelley, 25 Ind. 278 (1865), finding that although the word is “not to be found in any vocabulary of the English language, [it]is as well understood as any other English word.” The court said it isn’t found in “standard lexicons” because of its “vulgarity.” This was a case of a braggart saying he (you know what) to a woman “one hundred times.” The court did it to him in turn.
— Edgar v. McCutchen, 9 Mo. 768, 768 (1846). Thanks to John M. Baker and Kevin McDowell.