from
The Collaborative International Dictionary of English v.0.48
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.]