Giet is a mixture of letter G and the term Jit. This is another expression for homie, buddy, bro, bruh, pal and comrade. It's like calling someone a friend but fancier and more entertaining to both parties. It is typically used as a greeting, it can also be used to call out to somebody when you forget their name and you are close with the person.
Originally from Florida, created by a black Florida man.
