I just learned this term, and in a rather unusual way — I saw its Russian equivalent in a Russian translation of an article of mine. (The translation was by someone else, but I’m proofreading it right now.) The Russian word, which I also hadn’t known, is пасквиль, and the English analog is pasquinade. What does it mean? You can find the answer here. You can also see the word in action in this First Circuit opinion, which is written (unsurprisingly) by Judge Selya, who is known for liking such obscure — and sometimes even sesquipedalian — terms.