grader vs critic

grader and critic both are nouns.

Word	Noun	Adjective	Verb	Adverb
grader	Yes	No	No	No
critic	Yes	No	No	No

As nouns, critic is a hypernym of grader; that is, critic is a word with a broader meaning than grader:

grader (noun)	critic (noun)
a judge who assigns grades to something	a person who is professionally engaged in the analysis and interpretation of works of art
	anyone who expresses a reasoned judgment of something
	someone who frequently finds fault or makes harsh and unfair judgments