applicant vs worker

applicant and worker both are nouns.

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

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

applicant: a person who requests or seeks something such as assistance or employment or admission
worker: a person who acts and gets things done

Other hypernyms of applicant include actor, doer.

applicant (noun)	worker (noun)
a person who requests or seeks something such as assistance or employment or admission	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