Sister of Rachel (4)
I believe the answer is:
leah
'sister of rachel' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for leah that I've seen before include "Jacobs first wife (Gen.29)" , "Heal (anag) - girl" , "Hale (anag) - wife of Jacob" , "Jacob's first wife (Bible)" , "She married Jacob" .)