What is a Slut?: He Says vs She Says

So every once in a while Hubby will get bored and just throw a question out into the air to see my reaction.  The other day he came up and asked me, "How do you define a 'slut?"

Of course, my first reaction was, "Uh?  What have you been smoking?" 

It evolved eventually into each of us describing what defined a "slut?"  Now historically the word is based on 'slattern; a woman who is a messy housekeeper.'  We were arguing on it's modern usage.  Since Hubby is a man, his answer was very simple: "a woman who has had 'x' number of men, usually dresses really cheap."  (He couldn't settle on a definitive number, probably in an attempt to spare me from having to kill him.)