mettle vs temperament

mettle

noun
  • Good temperament and character. 

  • A quality of endurance and courage. 

adj
  • Spirited, vigorous, stout-hearted. 

temperament

noun
  • A person's usual manner of thinking, behaving or reacting. 

  • Individual differences in behavior that are biologically based and are relatively independent of learning, system of values and attitudes. 

  • A tendency to become irritable or angry. 

  • The altering of certain intervals from their correct values in order to improve the moving from key to key. 

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