impotence vs pusillanimity

impotence

noun
  • Powerlessness; incapacity. 

  • Inability to copulate or beget children; sterility, erectile dysfunction, etc. 

pusillanimity

noun
  • The quality or state of being pusillanimous; the vice of being timid and cowardly, and thus not living up to one's full potential; pusillanimousness. 

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