Failing ward, it's suggested? (8)
I believe the answer is:
drawback
'failing' is the definition.
(thesaurus)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for drawback that I've seen before include "Disadvantage, problem" , "Obstacle" , "Fly in the ointment" , "Hindrance - retreat" , "Snag" .)