A-one vs topnotch

A-one and topnotch both are adjectives.

Word	Noun	Adjective	Verb	Adverb
A-one	No	Yes	No	No
topnotch	No	Yes	No	No

As adjectives, A-one and topnotch are synonyms defined as:

Other synonyms of A-one include ace, crack, first-rate, super, tiptop, top-notch, tops.

A-one (adjective)	topnotch (adjective)
of the highest quality	of the highest quality