What is Flatleaver?
1.
A person who leaves a group of people to go with another group, without excusing or dismissing himself.
Ed: What are you guys doing later?
Guys: Oh!, We don't know. Maybe catch a flick or something. What do you want to do?
Ed: I dunno, but that sounds good. Oh look, check out Kiki and her friends.
Ed: Later y'll I'm out!
Ed is classified as a flatleaver!
2.
If you are hanging out at a friends place and leave because you are bored or want to hang out with other friends. Originally comes from the U.K. term "flat" which means apartment.
If you come over tonight don't be a flatleaver like you were last night.