beholder vs doer

beholder and doer both are nouns.

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

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

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

Other hypernyms of beholder include actor, worker.

beholder (noun)	doer (noun)
a person who becomes aware (of things or events) through the senses	a person who acts and gets things done