High-quality (3-3)
I believe this clue is a double definition.
'high' is the first definition.
(associated in meaning)
'quality' is the second definition.
(similar in meaning)
(Other definitions for superior that I've seen before include "Monastic head" , "The largest of the Great Lakes" , "Higher ranking" , "A Great Lake; better" , "so condescending!" .)
(Other definitions for top-notch that I've seen before include "Grade 1" , "Wonderful" , "Excellent (informal)" , "Of the highest quality" , "First-rate" .)
'high-quality' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for prime that I've seen before include "Main; indivisible number" , "Brief" , "Of superior grade" , "Chief or most important, like a minister" , "Original" .)