top dog 
noun informal
A person who is successful or dominant in their field: he was a top dog in the City...
- My point is that our nature as simian mammals pretty much dictates that the top dogs in our political systems are going to be more concerned with maintaining their privileged positions than anything else.
- I would assume the vice president is your top dog in a shadow government.
- The city's latest ranking as the top dog number one place in Britain to do profitable business testifies to that.
- monosporous
- monostable
- monostachyous
- monostatic
- monostearin
- monostelic
- monostich
- monostichous
- monostomatous
- monostome
- monostrophic
- monostylous
- monosubstituted
- monosubstitution
- monosulcate
- monosulfiram
- monosulphide
- monosulphite
- monosyllabic
- monosyllabically
- monosyllabication
- monosyllabicity
- monosyllabism
- monosyllabize
- monosyllable