Sifflation

sifflation [sif-FLAY-shun]
n. whistling; esp. expert whistling

[Derives from French, sifflotemont ("whistling") or siffler ("to whistle"); the fla- comes from Latin "to blow"]

As far as I can tell, sifflation is not a real word in English. It does not appear in any dictionaries I own -- including unabridged dictionaries -- and it doesn't appear in on-line English language dictionaries, including dictionaries published in England. However, it is a word that appears a handful of times in books, written (I am sure) by Anglophones who also know French and likely assume that their readers can figure out what they meant.

Here is where I came across sifflation, in Edmund Morris's biography of Teddy Roosevelt, Theodore Rex:

On March 4, the political season whistled to an end, literally, with some sifflation from the rostrum of the House of Representative Frank B. Fulkerson (R., Missouri).

When I Googled sifflation, I was directed to the word sufflation ("the act of blowing up or inflating"), which I sensed was not what Morris meant, though I recognized it having that same root fla-, meaning blow. Guessing that it might be a French word, I searched French-English dictionaries until I came across sifflotemont ("whistling") and siffler ("to whistle") and realized what Morris meant.

Another book, Maids in a Market by Clotilde Graves (published in London in 1894) confirmed for me that sifflation must have meant whistling in 19th Century Britain, and probably never crossed into the American lexicon and has since disappeared from the British:

Fanny whistled -- sifflation was an accomplishment of hers which Lady Jane profoundly disapproved of.