Ruth's mother-in-law (5)
I believe the answer is:
naomi
'ruth's mother-in-law' is the definition.
(biblical figure)
This is all the clue.
(Other definitions for naomi that I've seen before include "Ruth's mother-in-law (OT)" , "Biblical woman" , "-- Campbell, British model" , "Biblical mother-in-law of Ruth" , "mother- in-law" .)