booyakasha does infact mean kill the white man,
but ali g
contrary to common belief does not use the word Booyakasha to mean this.
ali g uses booyakasha, as a term for his home county BERKSHIRE.
staines is part of berkshire, hence 'da west staines massive'

Salutaion.
Form of greeting and hello's

straight from the mouth of Ali G himself, in an interview with spin.com

Could you translate your catchphrases "booyakasha" and "wagwaan"?

"Booyakasha" means "listen up rudeboi everytin irie whayaso lickylicky ya wangagot fifiman." "Wagwaan" means "booyakasha."

Actually it is a Jamaican patois approximation of the sound of a gunshot- you hold two fingers in the air and shout "BOOYAKASHA, BOO- BOO- BOOYAKASHA"

Booyakasha comes from the Irish word "buíochas" (pronounced bwee ah kuss) which mean "glory to" "or praise be" as in "buíochas le Dia" which means "thanks be to god". Oliver Cromwell sent 1000s of Irish to the plantations in Jamaica, and a lot of Irish (or Gaelic as non Irish people know it) words made it in to Jamaican patois. Another example is "Irie" from the Irish verb "Eirigh" (pronounced "Ire - ee") meaning to get up.

Don't know what it means but Ali G didn't make it up. Rapper KRS-One shouts it out at the beginning of "Keep Their Heads Ringin'" by Dr. Dre. In 1995. Before Ali G. Probably Jamaican roots then...

used by the genius Ali G, this word can be used in most situations

The approximated sound of a shotgun getting pumped... Ali G says it alot...