vassal vs liegeman

vassal and liegeman both are nouns.

Word	Noun	Adjective	Verb	Adverb
vassal	Yes	No	No	No
liegeman	Yes	No	No	No

As nouns, vassal and liegeman are synonyms defined as:

vassal and liegeman: a person holding a fief; a person who owes allegiance and service to a feudal lord

Other synonyms of vassal include feudatory, liege, liege subject.

vassal (noun)	liegeman (noun)
a person holding a fief; a person who owes allegiance and service to a feudal lord	a person holding a fief; a person who owes allegiance and service to a feudal lord