carry on war vs feud

carry on war

feud

verb
  • To carry on a feud. 

noun
  • A state of long-standing mutual hostility. 

  • An estate granted to a vassal by a feudal lord in exchange for service. 

  • A staged rivalry between wrestlers. 

How often have the words carry on war and feud occurred in a corpus of books? (source: Google Ngram Viewer )