fastener vs worker

fastener and worker both are nouns.

Word	Noun	Adjective	Verb	Adverb
fastener	Yes	No	No	No
worker	Yes	No	No	No

As nouns, worker is a hypernym of fastener; that is, worker is a word with a broader meaning than fastener:

Other hypernyms of fastener include actor, doer.

fastener (noun)	worker (noun)
restraint that attaches to something or holds something in place	sterile member of a colony of social insects that forages for food and cares for the larvae
a person who fastens or makes fast	a person who works at a specific occupation
	a member of the working class (not necessarily employed)
	a person who acts and gets things done