The German comes back downcast (3)
I believe the answer is:
sad
'downcast' is the definition.
(I've seen this in another clue)
'the german comes back' is the wordplay.
'the german' becomes 'das' ('the' in German).
'comes back' shows that the letters should be reversed in order.
'das' in reverse letter order is 'SAD'.
(Other definitions for sad that I've seen before include "Doleful" , "Dismal" , "Morose" , "Deplorable" , "Winter blues, initially" .)