Synonyms for Topnotch:

adj.

capital (adjective)
dandy, splendid.
champion (adjective)
super, topflight, capital, blue-ribbon.
classic/classical (adjective)
exemplary.
excellent (adjective)
super.
good (adjective)
exemplary, laudable, first-rate, good, commendable, praiseworthy, favorable, five-star, beneficial, admirable, nice, splendid, worthy, pleasant, worthwhile, fine, benign, excellent.
prize (adjective)
champion, top.
select (adjective)
tops.
super (adjective)
terrific, great, superb.
tiptop (adjective)
tiptop.
top-notch (adjective)
tiptop, five-star, fine, ace.
topnotch (adjective)
prime, superior, first-rate, excellent.

n.

capital, quality, great, prime, brag, terrific, champion, tophole, blue-ribbon, banner, superb, top, topflight, swell, first class, dandy, boss, bully. topnotch (noun)
first-rate, superior, tops, ace, a-one, tiptop, super.

Other synonyms:

tophole, blue-ribbon, topflight. first class. prime, champion, dandy. great. boss, terrific. quality. Other relevant words:
banner, superior, terrific, topflight, super, tiptop, bully, a-one, brag, tops, prime, quality, swell, champion, ace, dandy, superb, capital, tophole, top, blue-ribbon, first class, boss, great.