Lovely sound of Grieg's Holberg for one (5)
I believe the answer is:
sweet
'lovely' is the definition.
(thesaurus)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for sweet that I've seen before include "Term of endearment" , "Amiable" , "Tart, perhaps - or not tart" , "Sour companion" , "Pud" .)