slam-dunk, v. — Green’s Dictionary of Slang

slam-dunk v.

[basketball jargon slam-dunk, to slam the ball down through the basket, jumping high and using both hands]

1. (US black) to make an aggressive, powerful move.

1990		J. Wambaugh Golden Orange (1991) 54: Slam dunkin these little two-oh and five-oh dopers.
2000		Indep. on Sun. Rev. 27 Feb. 55: Diran Adebayo [...] who slamdunked the Saga prize for his debut Some Kind of Black.

2. to reject a request.

1990		S. Morgan Homeboy 239: The court, being disinclined to such a broad view of religious freedom, slamdunked it [i.e. a petition].
1992		R. Marcinko Rogue Warrior (1993) 7: Dickie gets slam-dunked and misses all the fun.