dieter vs worker

dieter and worker both are nouns.

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

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

Other hypernyms of dieter include actor, doer.

dieter (noun)	worker (noun)
a person who diets	sterile member of a colony of social insects that forages for food and cares for the larvae
	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