One in authority over others; a chief; usually, an overseer or boss.
2.
An arbiter.
3.
In the philosophy of Nietzsche, a man of superior physique and powers capable of dominating others; one fitted to survive in an egoistic struggle for the mastery.
...overman grimly, "that's what our lads weant believe in— your brometers, and pressures, and such like. They don't like to be teached by one who they say's ... — Son Philip • George Manville Fenn