topnotch vs tiptop

topnotch is not a noun while tiptop is a noun.

Word	Noun	Adjective	Verb	Adverb
topnotch	No	Yes	No	No
tiptop	Yes	Yes	No	No

As adjectives, topnotch and tiptop are synonyms defined as:

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

topnotch (noun)	tiptop (noun)
	the extreme top or summit
	the highest level or degree attainable; the highest stage of development

topnotch (adjective)	tiptop (adjective)
of the highest quality	of the highest quality