devotion vs inconstancy

devotion

noun
  • Feeling of strong or fervent affection; dedication 

  • The act or state of devoting or being devoted. 

  • Religious veneration, zeal, or piety. 

  • A prayer (often found in the plural) 

inconstancy

noun
  • Lack of constancy; lack of consistency in thought, emotion or action. 

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