A girl proficient in the art of "cock blocking". A Jayne will constantly follow and thrive off her one and only friend. If any interested male party attempts to hit on or even talk to this friend, the Jayne will immediately go on the defense. With a constant stare, the Jayne will then make it virtually impossible to interact with the girl you are attempting to talk to.
Friend : "Hey bro did you talk to that girl last night?"
You: "Na man, I didn't get a chance to. Her friend kept staying there third wheeling like crazy!
Friend: "Shit bro, looks like you've got a Jayne on your hands!"