perspicuity vs prudency

perspicuity

noun
  • Perspicacity; insight. 

  • Transparency; translucence. 

  • Clarity, lucidity, especially in expression; the state or characteristic of being perspicuous. 

prudency

noun
  • prudence 

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