Remedy or solution (4)
I believe the answer is:
cure
I believe this is a double definition.
'remedy' is the first definition.
(I know that remedy can be written as cure)
'solution' is the second definition.
(I've seen this in another clue)
(Other definitions for cure that I've seen before include "Make well again" , "Restore - kipper" , "Foreign priest" , "Parish priest in France" , "restore one to health" .)