Wretched end over European Union's accepting nothing (7)
I believe the answer is:
Here is my best explanation:
'wretched' is the definition.
('piteous' can be a synonym of 'wretched')
'end over european union's accepting nothing' is the wordplay.
'end' becomes 'tip' (tip is a kind of end**).
'over' is a reversal indicator.
'european union's' becomes 'eus'.
'accepting' is an insertion indicator.
'nothing' becomes 'o' (looks like zero - 0).
'tip' written backwards gives 'pit'.
'eus' enclosing 'o' is 'eous'.
(Other definitions for piteous that I've seen before include "Arousing sorrow and compassion", "Deserving sympathy", "Heart-rending", "Woeful" and "Deserving compassion".)