top-notch vs topnotch

top-notch and topnotch both are adjectives.

Word	Noun	Adjective	Verb	Adverb
top-notch	No	Yes	No	No
topnotch	No	Yes	No	No

As adjectives, top-notch and topnotch are synonyms defined as:

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

top-notch (adjective)	topnotch (adjective)
of the highest quality	of the highest quality