In generic terms, they all mean good. They're slang, of course, but they've come to be accepted in general English use.
The problem with slang is that it's ever evolving. (I'm still not sure what 'phat' means...). The other day someone on Twitter asked, "Is 'badassery' a word?" I replied she should check out the Oxford English Dictionary, the bible of the English language.
Yep, badassery is a word.
She was thrilled because now she is justified in using the word (wonder if it'll make the copyeditor's cuts...) and it's obviously recognized enough that people should know the meaning. This is one of the few which I think is self explanatory. 'Phat' is not.
Slang- love it or hate it, it's unavoidable.
'Fo' shizzle.'
Char
