Sunnybrook Farm girl (7)
I believe the answer is:
rebecca
'sunnybrook farm girl' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for rebecca that I've seen before include "Biblical wife of Isaac and mother of Jacob and Esau" , "Sunnybrook Farm girl" , "Daphne du Maurier's antiheroine" , "Daphne du Maurier novel; girl's name" , "also Isaac" .)