feudalism vs social system

feudalism and social system both are nouns.

Word	Noun	Adjective	Verb	Adverb
feudalism	Yes	No	No	No
social system	Yes	No	No	No

As nouns, social system is a hypernym of feudalism; that is, social system is a word with a broader meaning than feudalism:

feudalism: the social system that developed in Europe in the 8th century; vassals were protected by lords who they had to serve in war
social system: the people in a society considered as a system organized by a characteristic pattern of relationships

Other hypernyms of feudalism include social organisation, social organization, social structure, structure.

feudalism (noun)	social system (noun)
the social system that developed in Europe in the 8th century; vassals were protected by lords who they had to serve in war	the people in a society considered as a system organized by a characteristic pattern of relationships