any of a class of feudal serfs who by the 13th cent. had become freemen in their legal relations to all except their lord, to whom they remained subject as slaves
See villein in American Heritage Dictionary 4
also vil·lain(vĭlˈən, -ānˌ, vĭ-lānˈ)
noun
One of a class of feudal serfs who held the legal status of freemen in their dealings with all people except their lord.