cowardly vs poltroon

cowardly

adj
  • Showing cowardice; lacking in courage; weakly fearful. 

poltroon

adj
  • Cowardly. 

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

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