hearer vs beholder

hearer and beholder both are nouns.

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

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

hearer: someone who listens attentively
beholder: a person who becomes aware (of things or events) through the senses

Other hypernyms of hearer include observer, perceiver, percipient.

hearer (noun)	beholder (noun)
someone who listens attentively	a person who becomes aware (of things or events) through the senses