Widow owed rag in error (7)
I believe the answer is:
dowager
'widow' is the definition.
(dowager is a kind of widow)
'owed rag in error' is the wordplay.
'in error' is an anagram indicator.
'owed'+'rag'='owedrag'
'owedrag' is an anagram of 'DOWAGER'.
(Other definitions for dowager that I've seen before include "woman of property?" , "Rich old woman" , "Widow with inheritance" , "Rich old girl" , "Woman who holds title from dead husband" .)