A thot (that hoe over there) that you've already hit it with. Basically the left overs that you don't care about. They are so unimportant that they're merely an afterthot.
Like a cougar, but with no standards or dignity. Usually describes herself as a milf, but is usually just a rusty old ratchet. Is definitely old enough to know better... and you wish she would.
That afterthot just asked the dj to play Ricky Martin, said she was twenty-one, complimented his "ed hardy boys" shirt, then got upset when he said thank you, ma'am.