expediency vs prudency

expediency

noun
  • An expedient. 

  • The quality of being fit or suitable to effect some desired end or the purpose intended; suitability for particular circumstance or situation. 

  • Pursuit of the course of action that brings the desired effect even if it is unjust or unprincipled. 

prudency

noun
  • prudence 

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