rescuer vs worker

rescuer and worker both are nouns.

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

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

Other hypernyms of rescuer include actor, doer.

rescuer (noun)	worker (noun)
someone who saves something from danger or violence	sterile member of a colony of social insects that forages for food and cares for the larvae
a person who rescues you from harm or danger	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