observer vs beholder

observer and beholder both are nouns.

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

As nouns, observer and beholder are synonyms defined as:

observer and beholder: a person who becomes aware (of things or events) through the senses

Other synonyms of observer include perceiver, percipient.

observer (noun)	beholder (noun)
a person who becomes aware (of things or events) through the senses	a person who becomes aware (of things or events) through the senses
an expert who observes and comments on something