Gat
Gat is a slang term for gun. The word enjoys quite popular usage in late 20th/early 21st century African-American culture. Contributors to Urban Dictionary have proposed that this usage comes from the shortened form of Gatling gun.
"Gat" was also a common term for a gun in the early 20th century. It has been suggested that the lead character Gatsby of The Great Gatsby received his name from this slang term.
The word may also be used as a verb, e.g:
"Homie commin' at ya, Yah, you know I'm gunna gat ya." -Cypress Hill
References
Urban Dictionary definition of the word 'Gat'