arduousness vs deep water

arduousness

noun
  • The state of being arduous. 

deep water

noun
  • A difficult or embarrassing situation. 

  • Waters suitable for deep-draft ships, especially ocean-going. 

  • Used other than figuratively or idiomatically: see deep, water. 

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