When another female's ( or male's I don't judge ) bottom is particularly big.
Guy: Dude, look at Jessica today.
Guy 2: GYATT DAMN
Internet slang used to express the glorification of the distinguishable form (mainly buttocks and breasts) of a female with a curvy figure.
*Attractive female with a curvy form walks by*
A: "Gyatt Damn, B! She is one curvy gal!"
B:"Splendid, A. I couldn't agree more with you!"
Defines asses of all or any genders, particularly large or big fat round booty's
Anne, did you see the cake their serving?? I know, gyatt damn!!