Unexpected good fortune can be described in two ways: as a WINDFALL (8 letters) or manna from heaven (15 letters). A WINDFALL is an unexpected gain, usually of money or other valuable items. It is often used to describe a large sum of money that someone receives unexpectedly. Manna from heaven is a phrase used to describe something that is given to someone unexpectedly and is seen as a blessing. It is often used to describe a situation where someone receives something that they need without having to work for it.