Dearest sweet (4)
I believe the answer is:
love
This clue is a double definition.
'dearest' is the first definition.
(synonyms)
'sweet' is the second definition.
(thesaurus)
(Other definitions for love that I've seen before include "See 23" , "Vole (anag.)" , "Serenade" , "It's nothing in tennis" , "See 4" .)