From The Midwich Cuckoos by John Wyndham: “There was a pocket of silence in Midwich, broken only by the frouing of the leaves, the chiming of the church clock, and the gurgle of the Opple as it slid over the weir beside the mill . . .”
Frouing? I thought this was a typo at first. What it appears to be is a derivation — perhaps unique in English (since I can’t find any other examples of it or any dictionary citations, even online) — from frou-frou, which is a rustling sound as of silk. This in turn comes from the French for something decorative or fancy (particularly with regard to clothes). The French verb is froufrouter, to rustle.
I would like what Wyndham’s done, but I don’t think frouing sounds right in English. I guess it’s pronounced froo-ing, but I’d like to say frow-ing. In any event, it didn’t catch on and for all I know this is the only place it appears. Making it a kind of linguistic cuckoo itself.