Guilt-ridden
I believe the answer is:
ashamed
'guilt-ridden' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ashamed that I've seen before include "Feeling bad after unworthy action" , "Having painful regret for behaviour" , "Not proud" , "Afflicted with remorse, feeling sense of wrongdoing" , "hanging his head" .)