arduousness vs quagmire

arduousness

noun
  • The state of being arduous. 

quagmire

noun
  • A perilous, mixed up and troubled situation; a hopeless tangle. 

  • A swampy, soggy area of ground. 

verb
  • To embroil (a person, etc.) in complexity or difficulty. 

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