Joint ailment (4)
I believe the answer is:
gout
'joint ailment' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for gout that I've seen before include "Painful ailment, often of the foot" , "Inflammatory disease" , "Toe-swelling disease" , "Disease caused by excess uric acid in the bloodstream" , "Painful (joint) ailment" .)