roughrider
    n 1: a horseman skilled at breaking wild horses to the saddle

Roughrider \Rough"rid`er\, n.
   1. One who breaks horses; especially (Mil.), a
      noncommissioned officer in the British cavalry, whose duty
      is to assist the riding master.
      [1913 Webster]

   2. An officer or enlisted man in the 1st U. S. Volunteer
      Cavalry, a regiment raised for the Spanish war of 1898,
      composed mostly of Western cowboys and hunters and Eastern
      college athletes and sportsmen, largely organized, and
      later commanded, by Theodore Roosevelt. Sometimes,
      locally, a member of any of various volunteer cavalry
      commands raised in 1898. [Colloq.]
      [Webster 1913 Suppl.]