Also found in: Wikipedia.
(Historical Terms) a raider in the border country of England and Scotland in the mid-17th century
[C17 moss, in northern English dialect sense: bog]
moss•troop•er(ˈmɔsˌtru pər, ˈmɒs-)
1. a marauder who operated in the mosses, or bogs, of the border between England and Scotland in the 17th century.
2. any marauder.