The government. It's the most fearsome G word in the English language. It's utterance elicits a sense of dread and conjures up a feeling of incompetence.

The gravitational constant. Ironically, even though it’s called big G, it’s incredibly small.

A reference name for anything starting with the letter "G". Often used for "government" or a person's name, such as "Gerry".

1. The "G" is short for government
"Big G" is shouted as a heads up by the lookout as a warnning to his or hers accomplices that (police,correctional officer)are near their location. So that they can avoid being spotted.

A Big G is a person who openly exhibits homosexual tendencies. Short for Big Gay. Can be used to make someone think they are a Big Gangster, while everyone else in the group know he is just a Big Gay.

a person that like to say big g big g to what ever they can

and has a name like uummm barney lol
who is the big g wich could be big gay, or big gangster or basically anything lol
n like to call people gype :P

This term is widely used in the hip hop community and is a slang for Biggest Gangster.
It started back in 1960's in New york by local folks around bronx.