The feudalist insisted that the bond between lords and peasants was the foundation of social order.

feudalist 是由名词 feudalism（封建主义）加上后缀 -ist 构成的名词，-ist 表示"某种主义或制度的支持者或实践者"，所以 feudalist 指"封建主义者"或"封建制度的拥护者"。