superstar vs ace

superstar and ace both are nouns.

Word	Noun	Adjective	Verb	Adverb
superstar	Yes	No	No	No
ace	Yes	Yes	Yes	No

As nouns, superstar and ace are synonyms defined as:

Other synonyms of superstar include adept, champion, genius, hotshot, maven, mavin, sensation, star, virtuoso, whiz, whizz, wiz, wizard.

superstar (noun)	ace (noun)
someone who is dazzlingly skilled in any field	a serve that the receiver is unable to reach
	one of four playing cards in a deck having a single pip on its face
	someone who is dazzlingly skilled in any field
	the smallest whole number or a numeral representing this number

superstar (adjective)	ace (adjective)
	of the highest quality