A slam dunk
/ə ˈslæm dʌŋk/informalUS · UK
What does “A slam dunk” mean?
A slam dunk means something expected to succeed easily
A team facing much weaker opponents may think the next match is a slam dunk. The phrase expresses confidence, not proof that they will win.
It also works outside sport, such as for an application that seems certain to be accepted. The speaker can still turn out to be wrong.
When do people say it?
Use it for a result that seems almost certain. “Not a slam dunk” warns that success will take work or is not guaranteed.
“With three champions on our team, we thought the final was a slam dunk.”
Is it formal or informal?
Register: informal. It is most at home in everyday conversation rather than formal writing. Most common in US and UK.
Where does it come from?
In basketball, a slam dunk puts the ball straight down through the hoop. The figurative use borrows the idea of a decisive success.
Origin confidence: Disputed; treat with caution
How do you say “A slam dunk” in other languages?
Related idioms
- A walk in the park, something that is very easy to do
Last updated 2026-10-01