Horrified! Part of bag has torn! (6)
I believe the answer is:
aghast
'horrified' is the definition.
(thesaurus)
'part of bag has torn' is the wordplay.
'part of' indicates a hidden word.
'AGHAST' is hidden within 'bag has torn'.
(Other definitions for aghast that I've seen before include "Horrified, filled iwth consternation" , "Filled with consternation or horror" , "Shocked, dumbfounded" , "Appalled, shocked" , "Stunned" .)