A phrase used mainly to end a relationship. Once this is said, you will most likely never have contact with the other person despite the meaning of what was said.
Girl: I think we should break up, let's-just-be-friends.
Guy: Alright, i'm okay with that.
*2 months later*
Friend: Have you heard from -- lately?
Guy: Dude we haven't talked since we broke up.
Friend: Didn't she say she wanted to stay friends?
Guy: I guess not, no one ever actually means that.