diplomacy vs mordancy

diplomacy

noun
  • Tact and subtle skill in dealing with people so as to avoid or settle hostility. 

  • The art and practice of conducting international relations by negotiating alliances, treaties, agreements etc., bilaterally or multilaterally, between states and sometimes international organizations, or even between polities with varying status, such as those of monarchs and their princely vassals. 

mordancy

noun
  • The state or quality of being mordant. 

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