observer vs worker

observer and worker both are nouns.

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

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

observer: a person who becomes aware (of things or events) through the senses
worker: a person who acts and gets things done

Other hypernyms of observer include actor, doer.

observer (noun)	worker (noun)
a person who becomes aware (of things or events) through the senses	sterile member of a colony of social insects that forages for food and cares for the larvae
an expert who observes and comments on something	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