overdog means someone who is dominant or has a significant advantage in their field. Lexicurio rates it Sui generis — a strength score of 91 out of 100.
noun
- someone who is dominant or has a significant advantage in their field“Yet Truman, facing the resistance of his own State Department, was frequently irritated by Zionist lobbying and was wary of any sign of the Jewish underdogs becoming the bullying overdogs:”