The full form of PHAT is Pretty Hot And Tempting
What Does PHAT Mean?
‘Phat‘ is ‘Pretty Hot And Tempting‘ a phrase mostly used between guys saying, ‘hey man that chick over there is super hot and I want to go try and get with her.’

Origin of PHAT
The word ‘phat’ actually was created in the 1990s by songwriters in hip-hop and r&b genres explaining how a beat is super fly and funky. One of those songs you want to get up and move for. Then later in the late 2000s it has become more of a way to say hey look how hot someone is. However, in Australia it is known to mean ‘great wealth and fortune’ and known for being of Vietnamese origins.

Conversation Examples
Texter 1: Did you see the new girl in school!?
Texter 2: No, I was stuck in science getting caught up after that last test I missed.
Texter 2: Why?
Texter 1: OMG man she is so phat!
Texter 2: Yes, finally a good looking girl who don’t know what screw ups we are.
Texter 1: IKR
Texter 2: LOL