Defenestrate: throwing someone out of a window
I first read it in an Eddings novel, and thought he made it up.
It sounds as if a Dutch word ended up in English... only the Dutch version doesn't exist.
In "defenestrate" I see "fenest(e)r", which looks and sounds the Dutch word "venster"; and this word actually is the Dutch word for "window". Therefore the Dutch translation of "defenestrate" would become "ontvensteren", and that word doesn't exist, as far as I know.