poltroon vs pusillanimous

poltroon

adj

  • Cowardly. 

noun

  • An ignoble or total coward; a dastard; a mean-spirited wretch. 

pusillanimous

adj

  • Showing ignoble cowardice, or contemptible timidity. 

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