underdog
n.
"the beaten dog in a fight," 1887, from under + dog, n.. Compare top dog "dominant person in a situation or hierarchy" (see top, adj.).
I'm a poor underdog
But tonight I will bark
With the great Overdog
That romps through the dark.[from "Canis Major," Robert Frost, 1928]
But tonight I will bark
With the great Overdog
That romps through the dark.[from "Canis Major," Robert Frost, 1928]