feebleness vs fragility

feebleness

noun
  • The quality or state of being feeble; debility; infirmity. 

fragility

noun
  • Weakness; feebleness. 

  • The condition or quality of being fragile; brittleness; frangibility. 

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