noun. A person who your girlfriend seemingly needs to work on a project with. What really happens is, they go over to their house and fuck. Although some projects may be legit, the majority are made up. Closely related to a fuck buddy, but for a "supposed" educational purpose. This is your lover's excuse to cheat on you.
Girlfriend: "Hey Josh, I cant hang out with you at all on Saturday because i have to go to this guy's house to work on a project."
Josh: "For what class? Can I help?"
Girlfriend: "For(hesitates)...English. You wont understand it, and he(project buddy) is really smart. But dont worry Josh, he's just a really good friend!"
Josh: "Have fun with your project buddy"
This is bullshit. She's going over there to fuck. Dont be fooled.