interjection / noun
whoopee
woo-PEE/wʊˈpiː/
An expression of exuberant excitement or celebration.
Whoopee, the birthday surprise worked, she cries with her hands raised joyfully!

Etymology
Whoopee extends whoop, an excited cry, and was recorded with the meaning “noisy, unrestrained revelry.” As an exclamation, it makes that exuberance a direct expression of delight.
More examples
- Whoopee, school is out for the summer!
- "Oh, whoopee, another meeting," he says with a sigh.
- The wedding guests make whoopee until dawn.
Similar words
- hooray
- Expresses celebration or approval, often as a group cheer.
- yay
- Often expresses casual pleasure rather than exuberant celebration.