kneeler vs doer

kneeler and doer both are nouns.

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

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

Other hypernyms of kneeler include actor, worker.

kneeler (noun)	doer (noun)
a board (sometimes cushioned) for someone to kneel on	a person who acts and gets things done
a person in a kneeling position