Feeling sorry for a German wearing wig (6)
I believe the answer is:
rueing
'feeling sorry for' is the definition.
(I've seen this before)
'a german wearing wig' is the wordplay.
'a german' becomes 'ein' ('a' in German).
'wearing' means one lot of letters goes inside another.
'wig' becomes 'rug' (rug is a slang term for a wig).
'ein' inserted inside 'rug' is 'RUEING'.
(Other definitions for rueing that I've seen before include "Feeling regret" , "Feeling sorry for" , "Bitterly regretting (longer spelling)" .)