Cos ‧ sack /ˈkɒsæk $ ˈkɑːs-/ BrE AmE noun
a member of a people who lived on the plains of southern Russia and Ukraine, famous for their skill at fighting and at riding horses, and for their Russian dancing with the knees bent, the body low, and the arms folded in front of the body.
—Cossack adjective :
Cossack horsemen