Updated: Mar 21, 2020
Dictionary.com defines Woo-hoo as:
1) used to express excitement, delight, etc.: Woo-hoo! It's Friday!
Urban Dictionary defines Woo-hoo as:
1) Extreme satisfaction. There is really no other way to say it. Famous from use on The Simpsons.
I just got a hundred cars for free! Woohoo!
The Heavy Jack 3 define Woo-hoo as:
It's not my HEAVY problem