A project or more commonly the projects is a slang term in American English referring to government owned housing for low income residents. so a project girl is a girl who grew up in the projects.
-A fat chick that has potential, you just need to put in work by getting her big ass in the gym
-A chick who's hot, but is a loser and has no goals, so you have to motivate her and force her to get her life together
Guy 1: What do you think about Lisa?
Guy 2: Nah she's a project girl, too much work yo