be a slam dunk

be a slam dunk

To be predicted or expected to be successful; to be something that achieves success or a certain goal easily. All the best players in school are on our team—victory will be a slam dunk! I thought it would be a slam dunk to pass, but the bill didn't even make it out of committee.

See also: dunk, slam

be a ˈslam dunk

(American English) be something that is certain to be successful: The case looked like a slam dunk for the prosecution.

In basketball, a slam dunk is the act of jumping up and putting the ball through the net with a lot of force.

See also: dunk, slam