Green’s Dictionary of Slang

phat adj.

[deliberately skewed sp. of fat adj. (1c); but also popularly linked to a variety of suggested acronyms, e.g. physically attractive or pretty hips and thighs or pretty hips, ass and tits, or pretty hot and tempting, or pussy, hips, ass and thighs etc.]

1. (orig. US black/campus) used to describe an attractive woman.

[US]Time 2 Aug. 14: Negro argot... Mellow, phat, stone, boss. General adjectives of approval.
[US]Eble Campus Sl. Nov. 3: phat – nice looking and shapely, applied to females.
[US]Eble Campus Sl. Fall 5: phat – good looking female.
[US]Simon & Burns Corner (1998) 195: All these girls got so phat and fine over the winter, you know.
[US]Other Side of the Wall: Prisoner’s Dict. July [Internet] Phat: Pretty Hot And Tempting (attractive female).
[US]N. McCall Them (2008) 15: ‘She good–lookin’?’ ‘Phatter than a Bojangles biscuit wit butter.’.

2. (also phat-ass, phatman sweet) a general term of approval, admiration; also in phrs., e.g. phat 2 death.

[US]Eble Campus Sl. Nov. 6: phat – hip, cool, trendy.
[US]Source Oct. 120: Beautiful young urbanites living in phat apartments despite their shitty day-job incomes.
[US]Eble Campus Sl. Nov. 9: phat 2 death – epitome of coolness: ‘Ms. Herbert, even though you are a teacher, you phat2death.’.
[US]W. Shaw Westsiders 75: What you’re about to hear are some of the phattest unsigned acts to come across my desk.
Urban Dict. [Internet] I slapped on my phat hat and my phat-ass pants.
Urban Dict. [Internet] I can’t believe Christy juggled my nuts in her mouth. That’s so phatman sweet! Watch my jimmy.
[US]G. Goodwin [book title] Gordon Goodwin’s Big Phat Saxophone Duets.

3. large, powerful.

[UK]V. McDermid Insidious Intent (2018) 92: [T]he perfect drag strip for boy racers to burn rubber in their pimped-out hatchbacks, the roar of their phat exhausts splitting skulls.

In compounds

phat-cat (n.)

(US campus) a very fashionable person.

[US]Eble Campus Sl. Nov. 9: phat-cat – very stylish person.
phat pocket (n.)

(US black) a wealthy person; also attrib.

[US]P. Atoon Rap Dict. [Internet] phat pocket (n) A person who has a lot of money.
[US]K. Scott Hall Off the Charts 141: I don’t like that phat pocket peckerwood Vanderwall any more than you do.
[US]G. Hayward Corruption Officer [ebk] cap. 2: He was another get-money Harlem cat whose pockets stayed phat.
phat tape (n.) (also fat tape)

(US black teen) an exceptionally good mix tape.

Ice-T ‘I Ain’t New Ta This’ [lyrics] Home Invasion [album] I got to make a break hardcore fat tape / Word, I don’t fantasize, I don’t exaggerate / Just kick correct with the 1-2 mic check / Still quick to swing, take a sucker to the deck.
R. Swift in Vinyl Exchange Jun. [Internet] These days people feel the hottest mix tapes are the ones with the unheard exclusive songs. In addition some of the so-called ‘DJs’ which these people look up to and respect don’t even use turntables. Instead they use DAT machines and tape decks. Therefore, I set out to prove that you don’t have to play exclusives in order to produce a phat tape.