Underdog

Originally an American coinage for the beaten dog in a dog fight, where the beaten dog usually lies under the winning dog. First usage in a dogfighting context dates from 1887. Thereafter. the word soon adopted its current usage and figurative meaning for any person, or team, usually in a sporting context, that is the unfavoured or disadvantaged competitor, and therefore unlikely to win. The word is now Standard English throughout the English-speaking world with its dogfighting heritage largely forgotten.