Much more than miffed (5)
I believe the answer is:
irate
'much more than miffed' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for irate that I've seen before include "Fuming" , "having got in wax" , "Aggrieved" , "Hacked off" , "become irritated" .)