concordat vs impropriety

concordat

noun
  • A formal agreement between two parties, especially between a church and a state; specifically, an agreement between the Pope and a government. 

impropriety

noun
  • The condition of being improper. 

  • An improper act. 

  • Improper language. 

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