1 vs ace

1 and ace both are nouns.

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

As nouns, 1 and ace are synonyms defined as:

Other synonyms of 1 include I, one, single, unity.

1 (noun)	ace (noun)
the smallest whole number or a numeral representing this number	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

1 (adjective)	ace (adjective)
used of a single unit or thing; not two or more	of the highest quality