gloaming vs sundown

gloaming

noun
  • Twilight, as at early morning (dawn) or (especially) early evening; dusk. 

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 gloaming and sundown occurred in a corpus of books? (source: Google Ngram Viewer )