First-class (3,5)
'first-class' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for top-notch that I've seen before include "Excellent (informal)" , "Superb" , "Grade 1" , "Wonderful" , "First-rate" .)
'first-class' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for top shelf that I've seen before include "adult" , "Where blue material may be found" .)