Feel bitter, then dispatched again (6)
I believe the answer is:
resent
'feel bitter' is the definition.
(I've seen this before)
'dispatched again' is the wordplay.
I cannot really understand how this works, but
'dispatched' could be 'sent' (I've seen this before) and 'sent' is located in the answer.
'again' could be 're' (prefix meaning 'again') and 're' is located in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'then' is the link.
Can you help me to learn more?
(Other definitions for resent that I've seen before include "Object to" , "Feel hurt, insulted, about" , "Find objectionable" , "Dislike" , "being put in post again" .)