Shame about son taken in to a greater extent (7)
I believe the answer is:
remorse
'shame' is the definition.
(thesaurus)
'about son taken in to a greater extent' is the wordplay.
'about' becomes 're' (common abbreviation for 'with reference to').
'son' becomes 's' (genealogical abbreviation for son).
'taken in' indicates putting letters inside.
'to a greater extent' becomes 'more' (synonyms).
's' placed inside 'more' is 'morse'.
're'+'morse'='REMORSE'
(Other definitions for remorse that I've seen before include "Guilt for a wrong deed" , "Self-reproach" , "Distress from a sense of guilt" , "Regret for wrong" , "Regret or sorrow for wrong-doing" .)