An underdog is a person or team expected to lose a competition or struggle. The underdog lacks advantages that others have: maybe they're smaller, less experienced, have fewer resources, or face a much stronger opponent.

In sports, the underdog might be a team with a losing record playing against the champions. In a school election, the underdog candidate might be running against someone more popular. In a spelling bee, the underdog might be the youngest competitor facing off against older students.

The word carries a sense of rooting for someone facing long odds. People often cheer for the underdog because victories against tough opposition can feel more meaningful than easy wins. There's something inspiring about watching someone succeed despite the disadvantages stacked against them.

When an underdog actually wins, it's called an upset. These surprising victories can become legendary stories: the scrappy team that defeated the champions, the unknown competitor who stunned everyone by winning. Real-life underdog stories remind us that determination, preparation, and heart can sometimes overcome superior size, experience, or resources. History celebrates underdogs who refused to give up just because others expected them to fail.