prisoner vs prisoner of war

prisoner

noun
  • A person who is or feels confined or trapped by a situation or a set of circumstances. 

  • Any person held against their will. 

  • A person incarcerated in a prison, while on trial or serving a sentence. 

prisoner of war

noun
  • A combatant or soldier who is captured by an enemy power during or immediately after an armed conflict. 

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