expression, godan verb (-ku)
happen suddenly; appear out of the blue
Describes an event, idea, or situation that arises completely unexpectedly, as if falling from the sky. Often used with nouns like 話, 問題, or チャンス.
そんなうまい話が降って湧くわけがない。
There's no way such a sweet deal would just fall into our laps.
降って湧いたようなチャンスを逃すな。
Don't miss a chance that came out of nowhere.