A non descript exclamation which usually accompanies alot of hooting and whistling at whatever is causing the excitement. Most likely coined in the southern states of north America (eg Texas). Can also be used to punctuate traditional country and western music.
It might also be exclaimed by the rider of a bull or bucking bronco at a rodeo or their spectators.

The best answer to literally anything

If you're southern, got a little redneck in you or you're happy you can say YEEHAW!

A crazy country person who disagrees with city folk. A farmer or southern person.

An interjection of excitement, generally indicative of delight. Note: The more the pronunciation is drawled (slowed down), the more it is emphasized.

A shot of Jack Daniels chased with a double shot of fresh squeezed OJ. Yee Haw!!!

/ˈji/ /hɔː/

Oft conflated with gee haw: right and left, respectively, TWO commands for controlling a beast of burden with respect to the current path. The current expression is the result of the phonologically entertaining velar abandonment of gee /dʒiː/ for slothen vowel yee