darkness vs sundown

darkness

noun
  • The state of being dark; lack of light; the absolute or comparative absence of light. 

  • Lack of knowledge; obscurity or meaning or intelligibility; the unknown. 

  • Secrecy; concealment. 

  • The product of being dark. 

  • Gloom; gloominess; depression. 

  • Hell. 

  • The state or quality of reflecting little light, of tending to a blackish or brownish color. 

  • Lack of understanding or compassion; spiritual or mental blindness. 

sundown

noun
  • Sunset. 

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

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

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