strength vs verve

strength

noun
  • The intensity of a force or power; potency. 

  • The quality or degree of being strong. 

  • The strongest part of something; that on which confidence or reliance is based. 

  • A positive attribute. 

verve

noun
  • Enthusiasm, rapture, spirit, or vigour, especially of imagination such as that which animates an artist, musician, or writer, in composing or performing. 

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