underdog
/ˈəndɝˌdɔɡ/
a competitor thought to have little chance of winning
underdog in a sentence
“The underdog defeated the reigning champions.”
Origin of underdog
From dogfighting, the losing dog ending up under the other
Related Words
upset
an unexpected victory by a weaker opponent
seeding
ranking competitors to determine tournament matchups
bracket
a tournament structure showing matchups and progression
overtime
additional playing time when scores are tied
shutout
a game in which one side fails to score
blowout
a game with a lopsided score