Son of Isaac and Rebecca (4)
I believe the answer is:
esau
'son of isaac and rebecca' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for esau that I've seen before include "Jacob's twin (Bible)" , "Biblical man who sold his birthright for a mess of pottage" , "First son of Isaac (Bible)" , "Jacob's twin brother" , "Rebecca's son" .)