Trouble, contention (6)
I believe the answer is:
strife
I believe this is a double definition.
'trouble' is the first definition.
(thesaurus)
'contention' is the second definition.
(I've seen this before)
(Other definitions for strife that I've seen before include "Contention or contest" , "Heated discord" , "Trouble, hassle" , "Bitter disagreement" , "Warfare" .)