cottar vs holdfast

cottar and holdfast both are nouns.

Word	Noun	Adjective	Verb	Adverb
cottar	Yes	No	No	No
holdfast	Yes	No	No	No

As nouns, holdfast is a hypernym of cottar; that is, holdfast is a word with a broader meaning than cottar:

cottar: fastener consisting of a wedge or pin inserted through a slot to hold two other pieces together
holdfast: restraint that attaches to something or holds something in place

Other hypernyms of cottar include fastener, fastening, fixing.

cottar (noun)	holdfast (noun)
fastener consisting of a wedge or pin inserted through a slot to hold two other pieces together	restraint that attaches to something or holds something in place
a peasant farmer in the Scottish Highlands