G
1) A gangsta. "I'm a real G"
2) To have sex. "I got a bitch who loves to G"
3) Thousand. "Droppin' skills from now to the year 2-G (=2000)."

Gaffle
To harass. "The fuckin' pigs always gafflin' me."

Game
1) What you represent, what you got.  "Recognize my game, I run yo' whole crew."
2) The reality, the business, like the rap game, the game of life, the game of drugs, etc.

Gangbang
1) To commit a crime while being in a gang.
2) To have an orgy.

Gangster
A gangster, a criminal. "Never forget you fuckin' with a real gangsta here."

Gangsta lean
Gangsta's paradise.

Gank
To diss, to hurt, to damage.

Gasface
Disrespecting, showing someone you don't like him, you diss him. "You say you so cool, then why you always gettin' gasfaced? "

Gat/Gatt
A gun.

Get busy
Have sex. "Come on baby, let's get busy."

Get head/Give head
To get/give oral sex. "I caught my bitch with my best friend, givin' him head!"

Get your swerve on
Prepare to show skills. If you got your swerve on, it means you succeeded.

Ghetto Bird
Police helicopter.

Glock
A 9 mm gun. "The glock was locked."

Government cheese
Welfare. "I can't make no G's, so I gotta live on government cheese."

Grill
Yourself, your teeth. "Protect ya grill."

Grip
1) The skills on the mic. "I grips mics, I rips mics in half."
2) Money.

Guage
A shotgun. "I got the 12 Guage loaded and ready to fire."