People who lose in a fair competition, and thus seek out less than graceful means of expressing their disatisfaction with and inability to handle losing like an adult.
See: Republicans and Tea Party attendees are sore losers.
A sore loser is someone who loses in a fair competition but whines about it on a constant basis, blaming everyone around them for their loss except themselves. Fun to taunt, but no fun to play with.
"Stop throwing chess pieces at me, ya damn sore loser!"
Someone who can't simply be honorable, by accepting defeat and/or trying again. On the contrary, said individual or group engages in childish pissing and moaning; bitching about how it's not fair and the other side cheated, etc.
Al Gore, Cynthia McKinney and John Kerry are all prime examples of winners. You won't find a single sore loser in that jolly little group!
someone who can't take a loss in stride.
Bill Belichick is the biggest sore loser of them all.
sore loser is someone who loses in a fair competition but whines about it on a constant basis or tries to change the rules to their advantage once its evident that they have lost.
Hillary Clinton is a sore loser.
One who consistently whines about losing a contest fair and square.
"That Nic Lee is being a real sore loser!"
A team that cries every time they lose.
The New England Patriots are sore losers. They cry and are very unprofessional on congratulating other teams that defeat them.