ace vs digit

ace and digit both are nouns.

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

As nouns, digit is a hypernym of ace; that is, digit is a word with a broader meaning than ace:

Other hypernyms of ace include figure.

ace (noun)	digit (noun)
a serve that the receiver is unable to reach	a finger or toe in human beings or corresponding body part in other vertebrates
one of four playing cards in a deck having a single pip on its face	one of the elements that collectively form a system of numeration
someone who is dazzlingly skilled in any field	the length of breadth of a finger used as a linear measure
the smallest whole number or a numeral representing this number

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