It means "Got Damn" in AAVE. it does not mean someone who has a phatty.
*cute girl walks past*
guy: Gyatt damn she fine
A large, volumptuous gluteus maximus that is quite attracting.
Person 1: GYATT!!
Person 2: Dawg its my sister and she's 14.
jamal: damn hoe gotta phatty( see's a foine ass girl with a phatty
jonquavvious: nahhh thats a gyattt oml
People say Gyatt particularly when they see a huge ass
She got that GYATT
A word to describe when a person has a big butt. It’s used like a holler.
“Damn look at her, bro.”
“Oh my GYATT. her ass is huge”