Consequence of quarrel (7)
I believe the answer is:
fallout
I believe this is a double definition.
'consequence' is the first definition.
(I know that fallout is a type of consequence)
'quarrel' is the second definition.
(I've seen this before)
'of' acts as a link.
(Other definitions for fallout that I've seen before include "A-bomb aftermath" , "Military order to leave formation" , "Quarrel, abandon friendship" , "Quarrel; go off parade" , "nuclear aftermath" .)