Someone who is both poor ( monetarily) and also is a loser or fails to achieve any sort of goal in life and can't take care of themselves or their kids.
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! How ever on the other side Gustavo costa, Mattheus Prais and more are all sore losers