1. Literally, a hand in poker consisting of four cards of the same suit and one that is different, i.e., one card short of a flush. I thought I'd finally win the hand, but when I drew the ace of spades, I was left with a busted flush.

2. A person, organization, or thing that at one time held great potential or influence but that ultimately ended up a failure. Jack left secondary school with great grades and a bright future, but he became addicted to drugs and turned out a busted flush. The company promised big returns to investors but turned out to be a busted flush.