Was the Feudal system a social system or a political system?

Feudal society was not just social - it encompassed everything social, political and economic. On the whole, you were either an Elite (royalty/aristocrat/land owner), an Ecclesiastical figure (involved with the Church eg a Bishop, Priest, etc) or a Serf (a peasant). The Church and the State combined to dominate political life. Economically, serfs worked the land owned by the elites, and paid tithes (taxes) to the Church. Socially, serfs were the lowest of the low, with little or no rights and almost no chance of ever becoming free.