ace vs ace of spades

ace and ace of spades both are nouns.

Word	Noun	Adjective	Verb	Adverb
ace	Yes	Yes	Yes	No
ace of spades	Yes	No	No	No

As nouns, ace of spades is a hyponym of ace; that is, ace of spades is a word with a more specific, narrower meaning than ace:

ace: one of four playing cards in a deck having a single pip on its face
ace of spades: the ace in the spade suit; sometimes taken as a portent of death

Other hyponyms of ace include ace of clubs, ace of diamonds, ace of hearts.

ace (noun)	ace of spades (noun)
a serve that the receiver is unable to reach	the ace in the spade suit; sometimes taken as a portent of death
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

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