villein vs cottier

villein and cottier both are nouns.

Word	Noun	Adjective	Verb	Adverb
villein	Yes	No	No	No
cottier	Yes	No	No	No

As nouns, cottier is a hyponym of villein; that is, cottier is a word with a more specific, narrower meaning than villein:

villein: (Middle Ages) a person who is bound to the land and owned by the feudal lord
cottier: a medieval English villein

Other hyponyms of villein include cotter.

villein (noun)	cottier (noun)
(Middle Ages) a person who is bound to the land and owned by the feudal lord	a medieval English villein