Fighting a case (6)
I believe the answer is:
action
I believe this is a double definition.
'fighting' is the first definition.
(thesaurus)
'a case' is the second definition.
('action' can be a synonym of 'case')
(Other definitions for action that I've seen before include "Lawsuit; something done" , "Court case" , "Not CIA (anag)" , "The mechanism of, say, a watch" , "Fighting - lawsuit" .)