Foolhardy outbreak (4)
I believe the answer is:
rash
I believe this clue is a double definition.
'foolhardy' is the first definition.
(I know that foolhardy can be written as rash)
'outbreak' is the second definition.
(rash can mean a sudden outbreak)
(Other definitions for rash that I've seen before include "Foolish; skin problem" , "Hives" , "Flood" , "spate" , "Impetuous; skin ailment" .)