underdog

noun3

1. •
   A competitor thought unlikely to win.

   • They were the underdogs in the basketball competition.
2. •
   Somebody at a disadvantage.

   • Laszlo: Isn't it strange that you always happened to be fighting on the side of the underdog? Rick: Yes. I found that a very expensive hobby, too. But then I never was much of a businessman. — 1942
3. •
   A high swing wherein the person pushing the swing runs beneath the swing while the person being pushed is at the forward limit of the arc.