Evil middleman is upset but not dead (5)
I believe the answer is:
alive
'not dead' is the definition.
('alive' is the opposite to 'dead')
'evil middleman is upset' is the wordplay.
I cannot quite see how this works, but
an anagram of 'evil' is 'live' which is within the answer.
A single letter 'a' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'but' acts as a link.
Can you help me to learn more?
(Other definitions for alive that I've seen before include "Aware" , "Still in use, not dead" , "operative?" , "Extant" , "In existence" .)