Totally l33t, incredibly fine. As an adjective probably originated in Mexico.
Exclaimed after victory. ex. Boo-yaa, you just got served!
Originated in West Coast gangsta culture--simulating the sound of a shotgun blast. Originally popularized by Samoan gangsta rap group BooYa Tribe, later broadened its usage when ESPN's Stuart Scott used it to describe extremely exciting sports plays...slam dunks, in yo' face shot blocks, etc
Yaa-Boo term of defeat or disgust
Originated In Mexico from Carlos and Jayson aka The Boo-yaa Boyz