Team Jumper 

Going from liking one team to liking another.

Your such a team jumper. How can you go from likng Team1 to Team3

Team Jumper by slap a nap February 11, 2012

Team-jumper 

Came up with it while playing Battlefield 1942. This is a person who changes to the team with the most/all of the captured flags points rather than helping his own team take them back.

That no-talent team-jumper just went to the other side instead of helping us out!

Team-jumper by -WOODY- August 17, 2003