A faxy lady is a plus sized woman who is still totally hot. "Faxy" is fat plus sexy. It is also a play on words stemming from the 1970's phrase, "Foxy Lady". You must be at least a size 16 or larger to be considered a Faxy Lady.
Guy one: You see that big chick over there? I think I am gonna hit that tonight.
Guy two: I don't blame you, dude. That's one Faxy Lady!