Appeal involving trade union overturned and excluded (7*)
I believe the answer is:
Here is my best explanation:
'excluded' is the definition.
(I've seen this before)
'appeal involving trade union overturned' is the subsidiary indication.
I cannot quite understand how this works, but
'appeal' could be 'o' and 'o' is present in the answer.
'union' could be 'tu' (I've seen this in other clues) and 'tu' is present in the remaining letters.
The remaining letters 'shut' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'and' is the link.
(Other definitions for shutout that I've seen before include "Prevent from entering" and "Excluded".)