Madame Bovary is a classic novel (4)
I believe the answer is:
emma
This clue is a double definition.
'madame bovary' is the first definition.
(I've seen this before)
'classic novel' is the second definition.
(Jane Austen novel)
'is a' is the link.
(Other definitions for emma that I've seen before include "classic work" , "Madame Bovary, perhaps" , "Lady Hamilton or Lady Thompson?" , "Best Actress Oscar winner 1992, for 'Howard's End'" , "Titled heroine" .)