Dismayed as coffin mocked outside (8)
I believe the answer is:
appalled
'dismayed' is the definition.
('appalled' can be a synonym of 'dismayed')
'coffin mocked outside' is the wordplay.
'coffin' becomes 'pall' (I can't explain this - if you can you should believe this answer much more).
'mocked' becomes 'aped' (aping is a kind of mocking).
'outside' is an insertion indicator.
'pall' placed within 'aped' is 'APPALLED'.
'as' is the link.
Can you help me to learn more?
(Other definitions for appalled that I've seen before include "Shocked and horrified" , "Aghast, horrified" , "Greatly dismayed" , "Dismayed - aghast" , "Greatly horrified" .)