What is the origin of the idiom "slam dunk" and when to use it?

The idiom "slam dunk" originally comes from basketball, where it refers to a high-scoring and often visually impressive play where a player leaps and forcefully scores by putting the ball directly through the opponent's hoop. The term has since evolved into a widely used idiom that is used to convey a high degree of certainty, simplicity, or an easy, undeniable success in various contexts, not limited to sports.