Part of Ebonics since 1963! 
I think it was used in this film: http://en.wikipedia.org/wiki/Talk:Repo_Man_(film)
One edition of the Scrabble dictionary defines Phat as a printer's slang indicating that text is correctly typeset. Any other sources that give this definition? Maybe it originated as an acronym?--Theodore Kloba 17:08, 21 September 2007 (UTC)
This term has strong connotations and I'm not so sure it should be used in any 'official' definition of 'phat'. -- OlEnglish 00:44, 2 May 2009 (UTC)
Pretty, Hot And Tempting. I have seen this suggested as an acronym but I suspect it was thought up after the word was in use. -anon
The above has no author mark, so anon added. Re PHAT. For several years I have heard mention that it is an acronym. Looking through music magazines collected by university libraries or major libraries should provide a sense of the history of the word that can be traced, eg, earlier definitions, if they exist or the earliest mention of Pretty, Hot and Tempting. I've heard PHAT defined as an acronym for several years.
Jsemmel 16:09, 15 November 2011 (UTC)
- Acronyms are practically always folk etymologies. Fat doesn't seem unlikely, e.g. "phat beats" in a track are ones with a large, wide feel to them (if the musical sense came first — I don't know). Words meaning "large" have also commonly been used to mean "good, cool", e.g. great, massive. Equinox ◑ 16:12, 15 November 2011 (UTC)