war leader vs warlord

war leader

noun
  • A person who leads a people or military force in a war; a war chief, a warlord. 

warlord

noun
  • A high military officer in a warlike nation. 

  • A local ruler or bandit leader usually where the government is weak. 

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