Disadvantage of ward (8)
I believe the answer is:
drawback
'disadvantage' is the definition.
(drawback is a kind of disadvantage)
'ward' is the wordplay.
I cannot really see how this works, but
an anagram of 'ward' is 'draw' which is within the answer.
The remaining letters 'back' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
'of' acts as a link.
(Other definitions for drawback that I've seen before include "Disadvantage, problem" , "Hindrance - disadvantage" , "Limitation, disadvantage" , "Fly in the ointment" , "Hindrance - retreat" .)