murkiness vs sundown

murkiness

noun
  • The state or quality of being murky. 

sundown

verb
  • to experience an episode or an onset of some detrimental mental condition like agitation, anxiety, hallucination or dementia, daily at nightfall. 

noun
  • Sunset. 

  • A hat with a wide brim to shade the eyes from sunlight. 

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