Yahoo (noun)

1. A rude, uncivilized, or savage person.
2. An exclamation of joy or excitement.

Origin:

Derived from the character in jonathan swift's 'gulliver's travels' (1726), a race of brutes resembling men, who live in rough and brutal ways.

Examples:

1. The yahoo who cut in line was finally thrown out of the movie theater.
2. Yahoo! We won the lottery!
3. The man's behavior was that of a yahoo.
4. When they heard the news, they both yelled 'Yahoo!'.
5. The yahoo was covered in mud and smelled of alcohol.