Fighting to give cowards heart (3)
I believe the answer is:
war
'fighting' is the definition.
(thesaurus)
'cowards heart' is the wordplay.
'heart' indicates the central letters.
The middle letters of 'cowards' are 'WAR'.
'to give' acts as a link.
(Other definitions for war that I've seen before include "State of armed struggle" , "series of engagements" , "Sustained conflict" , "Armed hostility" , "Fight" .)