Actor in the southeast is a disgrace (5)
I believe the answer is:
shame
'a disgrace' is the definition.
(I know that disgrace can be written as shame)
'actor in the southeast' is the wordplay.
'actor' becomes 'ham' (ham is a kind of actor).
'in the' indicates putting letters inside.
'southeast' becomes 'SE' (synonyms).
'ham' placed inside 'se' is 'SHAME'.
'is' is the link.
(Other definitions for shame that I've seen before include "Ignomony" , "Disgrace - Salman Rushdie novel" , "disgraceful" , "Discredit - ignominy" , "pity!" .)