appraiser vs evaluator

appraiser and evaluator both are nouns.

Word	Noun	Adjective	Verb	Adverb
appraiser	Yes	No	No	No
evaluator	Yes	No	No	No

As nouns, evaluator is a hypernym of appraiser; that is, evaluator is a word with a broader meaning than appraiser:

appraiser: one who estimates officially the worth or value or quality of things
evaluator: an authority who is able to estimate worth or quality

Other hypernyms of appraiser include judge.

appraiser (noun)	evaluator (noun)
one who estimates officially the worth or value or quality of things	an authority who is able to estimate worth or quality
one who determines authenticity (as of works of art) or who guarantees validity