constancy vs disquiet

constancy

noun
  • The quality of being constant; steadiness or faithfulness in action, affections, purpose, etc. 

  • An unchanging quality or characteristic of a person or thing. 

disquiet

noun
  • Lack of quiet; absence of tranquility in body or mind 

verb
  • To make (someone or something) worried or anxious. 

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