Definitions

1. noun

a person who is extremely enthusiastic or excitable, especially one who is eager to take part in something

“The crowd erupted into a chorus of yahooing as the concert began.”

2. verb

to express or utter a loud, enthusiastic shout, typically in excitement or triumph

“The fans were yahooing as their team scored the winning goal.”

3. interjection

an expression of excitement or triumph

“Yahoo! We won the championship!”

4. proper noun

a popular internet service provider (historical)

“In the past, people used Yahoo to search for information online.”