Source : Webster's Revised Unabridged Dictionary (1913)

Overman \O"ver*man\, n.; pl. {-men}.
   1. 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.