### Clue: Furious about fellow coming back and ready finally to make a complaint (6)
### Answer: MALADY 
 ### Explanation: Definition: a complaint
 MAD(furious) **containing**(about) **reversal of**(… coming back) AL(a fellow's name) **plus**(and) **the last letter of**(… finally) "ready".
Defn: …, medically speaking.