Suspend scoundrel having a guilty look (7)
I believe the answer is:
hangdog
'having a guilty look' is the definition.
(a hangdog look is a guilty one)
'suspend scoundrel' is the wordplay.
'suspend' becomes 'hang' (to hang is to suspend from something).
'scoundrel' becomes 'dog' (dog is a kind of scoundrel).
'hang'+'dog'='HANGDOG'
(Other definitions for hangdog that I've seen before include "Appearing ashamed" , "With a guilty look" , "Downcast (expression)" , "With cowed expression" , "With a sneaking, cowed look" .)