gunship vs man-of-war

gunship

noun
  • A ship equipped with heavy artillery. 

  • An armed helicopter tasked to attack the enemy. 

  • A transport airplane equipped with large calibre guns typical of armoured fighting vehicles 

man-of-war

noun
  • A powerful armed naval vessel, primarily one armed with cannon and propelled by sails; a warship. 

  • A man whose occupation is fighting in wars; a soldier, a warrior. 

  • The Arctic skua (Stercorarius parasiticus). 

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