To have a windfall refers to:

Explanation

A 'windfall' refers to an unexpected gain or advantage, often financial in nature, such as winning the lottery or receiving an inheritance. The term originates from fruit or wood that the wind blows down, which can be collected freely. This is a positive event, unlike a calamity or bad weather, which are negative. While receiving gifts is unexpected, it doesn't capture the financial aspect that 'windfall' conveys.