Thesaurus.com
Dictionary.com

most first-class

ADJECTIVE
superior, excellent
Synonyms
WEAK
capital choice dandy fine first-string five-star in class by itself prime shipshape sound supreme tiptop top top-notch very good
Antonyms
WEAK
bad inferior lesser poor second-class/second-rate
ADJECTIVE
best
Synonyms
WEAK
excellent exclusive finest first-rate five-star prime shipshape superior tip-top top-drawer top-notch topflight
most first class
ADJECTIVE
superior, excellent
Synonyms
WEAK
capital choice dandy fine first-string five-star in class by itself prime shipshape sound supreme tiptop top top-notch very good
Antonyms
WEAK
bad inferior lesser poor second-class/second-rate
ADJECTIVE
best
Synonyms
WEAK
excellent exclusive finest first-rate five-star prime shipshape superior tip-top top-drawer top-notch topflight