WINDFALL

Wind″fall′ (?), n. 1. 1. Anything blown down or off by the wind, as fruit from a tree, or the tree itself, or a portion of a forest prostrated by a violent wind, etc. “They became a windfall upon the sudden.” Bacon.
2. 2. An unexpected legacy, or other gain.
He had a mighty windfall out of doubt. B. Jonson.