A completely average woman on the guy rating scale. She can be neither cute or ugly, shes just a 5.
Can also be used to describe a boyfriend/girlfriend that you're using to pass the time until a good one comes along.
Glen: Man dude, are there ever any cute chics in this place?
Walter: Nah man, this place is always full of fives!
Lloyd: Yeah, I've really been thinking about getting serious with my chic dude...
Walter: What?! You know that chics just a 5 man, even you can do better.