assurance vs imperturbability

assurance

noun
  • Firmness of mind; undoubting steadiness; intrepidity; courage; confidence; self-reliance. 

  • Subjective certainty of one's salvation. 

  • The act of assuring; a declaration tending to inspire full confidence; something designed to give confidence. 

  • Insurance; a contract for the payment of a sum on occasion of a certain event, as loss or death. Assurance is used in relation to life contingencies, and insurance in relation to other contingencies. It is called temporary assurance, in the time within which the contingent event must happen is limited. 

  • The state of being assured; total confidence or trust; a lack of doubt; certainty. 

  • Excessive boldness; impudence; audacity 

  • Any written or other legal evidence of the conveyance of property; a conveyance; a deed. 

imperturbability

noun
  • A state of calm, unruffled self-assurance; aplomb, composure. 

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