defiance vs observance

defiance

noun
  • A challenging attitude or behaviour; challenge. 

  • The feeling, or spirit of being defiant. 

  • Open or bold resistance to or disregard for authority, opposition, or power. 

observance

noun
  • The practice of complying with a law, custom, command or rule. 

  • That which is to be observed. 

  • Observation or the act of watching. 

  • A rule governing a religious order, especially in the Roman Catholic church. 

  • The custom of celebrating a holiday or similar occasion. 

  • Reverence; homage. 

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