England's affliction unknown (7)
I believe the answer is:
blighty
'england's' is the definition.
(Blighty is a nickname for Britain or England)
'affliction unknown' is the wordplay.
I cannot really understand how this works, but
'affliction' could be 'blight' (blight is a kind of disease) and 'blight' is located in the answer.
'unknown' could be 'y' (algebra) and 'y' is found in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for blighty that I've seen before include "home for soldiers" , "England (sl.)" , "Home Country"" , "Disease-ridden" , "Britain (slang)" .)