Shame about son going inside again (7)
I believe the answer is:
remorse
'shame' is the definition.
(thesaurus)
'about son going inside again' is the wordplay.
'about' says the letters should be written in reverse.
'son' becomes 's'.
'going' becomes 'rome' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'inside' indicates putting letters inside.
'again' becomes 're'.
's'+'rome'='srome'
'srome' backwards is 'emors'.
'emors' inserted into 're' is 'REMORSE'.
(Other definitions for remorse that I've seen before include "Compunction" , "A feeling of deep regret" , "Sorrow for wrongs committed" , "Pity" , "Penitence" .)