feebleness vs potency

feebleness

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

potency

noun
  • Concentration; strength 

  • Sexual virility: the ability to become erect or achieve orgasm. 

  • Potentiality, ability, capacity. 

  • Power, authority. 

  • The ability or capacity to perform something 

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