slam dunk
Concise Oxford English Dictionary © 2008 Oxford University Press:
slam dunk
▶noun
- 1 Basketball a shot thrust down through the basket.
- 2 N. Amer. informal a foregone conclusion or certainty.
- 1 Basketball thrust (the ball) down through the basket.
- 2 N. Amer. informal defeat or dismiss decisively.
'slam dunk' also found in these Oxford entries:

