thirster vs doer

thirster and doer both are nouns.

Word	Noun	Adjective	Verb	Adverb
thirster	Yes	No	No	No
doer	Yes	No	No	No

As nouns, doer is a hypernym of thirster; that is, doer is a word with a broader meaning than thirster:

Other hypernyms of thirster include actor, worker.

thirster (noun)	doer (noun)
a person with a strong desire for something	a person who acts and gets things done