What is a sIut. and how do you know if you dress like one?

Slut is this. Sunday late afternoon while standing at a bus stop, a 20 something White American female walks up. Big sunglasses, fake tan, tight asss dress 3 inches from her crotch, talking on her iphone of course. Her conversation went like this-"Omg, I was like sooooooo drunk last night. I've got a massive hangover, you know?"