Reportedly dressing well (6)
I believe the answer is:
source
'well' is the definition.
(thesaurus)
'reportedly dressing' is the wordplay.
'reportedly' shows a homophone (sound like).
'dressing' becomes 'sauce' (I've seen this before).
'sauce' sounds like 'SOURCE'.
(Other definitions for source that I've seen before include "Place or person where something begins" , "Beginning to add" , "'Origin, root (6)'" , "Where something originates" , "Spring, fountain head" .)