Thot

That stands for:
That Whore Over There
Thots are pretty much any girl or guy who has had more than 1-2 girlfriends or boyfriends in a week.

And a that is also most likely a slut, and they might act loose or bitchish

Girl 1: Hey, whose that over there?

Girl 2: Oh, that's the new girl. I heard she's already dating 3 or 4 guys, right now!

Girl 1: Soo... She's a thot?

Girl 2: Exactly.