As in chicken booyah A traditional dish made by Belgian immigrants in Northeastern Wisconsin. A chicken soup made over an open fire usually in batches of 15 gallons or more.
A mispronunciation of the word "bullion" (pronounced BOO-Lyahn), an exclamation stock traders sometimes make when executing a profitable deal. The word was misappropriated by douchebags with bad hearing to the meaningless word "Booyah".
Douchebag: "Booyah! I just found a nickel!"
Stocktrader: "Bullion! I just made $500K and wrecked your retirement nest egg!"
"Boo Yaa, at that time (c1990) was slang in the neighbourhood for the sound of a shotgun, so we used the term to describe the impact of us on stage, blowing people away." Thus spake Boo-Yaa Tribe.