commentator vs observer

commentator and observer both are nouns.

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

As nouns, commentator and observer are synonyms defined as:

commentator and observer: an expert who observes and comments on something

commentator (noun)	observer (noun)
a writer who reports and analyzes events of the day	a person who becomes aware (of things or events) through the senses
an expert who observes and comments on something	an expert who observes and comments on something