Cure-all (7)
I believe the answer is:
panacea
'cure-all' is the definition.
(synonyms)
This is all the clue.
(Other definitions for panacea that I've seen before include "comprehensive fix" , "A cure-all for diseases or troubles" , "Cure for all things" , "Remedy for wide variety of ills, a cure-all" , "that'll solve everything" .)