Not easy to translate into English, it meant "runner of the woods" but it had many connotations that were understood. They were an independent entrepreneurial French-Canadian trader who traveled in New France and the interior of North America, usually to trade with First Nations peoples by exchanging various European items for furs. Many learned the trades and practices of the Native peoples. They also intermarried with natives which the English rarely did, and their influence extended far beyond French Canada through the Great Lakes, into the mid-west and down the Mississippi. They were adept at bush craft and understanding and respecting native ways.
This came up with a pbem opponent who was surprised that the French were doing so well with low supplies, fighting it out in the wilderness over a fort that had been burned down in the course of the fighting. The unit types supply the reason: coureur des bois units give the entire stack a 15% supply consumption reduction in wild areas. The units involved in this classic wilderness fight against perfidious Albion: Le Sieur de Portneuf's Raiders, and Jacques le Moyne Sainte-Hélène's Raiders. Vive la France!