cotter vs serf

cotter and serf both are nouns.

Word	Noun	Adjective	Verb	Adverb
cotter	Yes	No	No	No
serf	Yes	No	No	No

As nouns, serf is a hypernym of cotter; that is, serf is a word with a broader meaning than cotter:

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

Other hypernyms of cotter include helot, villein.

cotter (noun)	serf (noun)
fastener consisting of a wedge or pin inserted through a slot to hold two other pieces together	(Middle Ages) a person who is bound to the land and owned by the feudal lord
a medieval English villein
a peasant farmer in the Scottish Highlands