Impetuous complaint (4)
I believe the answer is:
rash
I believe this clue is a double definition.
'impetuous' is the first definition.
(I know that impetuous can be written as rash)
'complaint' is the second definition.
(I've seen this before)
(Other definitions for rash that I've seen before include "Harum-scarum" , "Over-hasty, reckless" , "Careless" , "Ill-considered - outbreak" , "Incautious" .)