Remedy reform of taxation in failing area (9)
I believe the answer is:
antitoxin
'remedy reform' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'of taxation in failing area' is the wordplay.
I cannot really see how this works, but
'of' could be 'o' and 'o' is found in the answer.
'in' is present in the answer.
'area' could be 'a' (maths abbreviation) and 'a' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for antitoxin that I've seen before include "Treatment for poison" , "It neutralises poison in the body" , "treatment for snakebites?" , "Serum neutralising poisons" .)