adusk vs crepuscular

adusk

adj
  • Resembling conditions at dusk or twilight, low-lit, dark; in darkness, gloomy. 

adv
  • At dusk; in the dusk or twilight. 

crepuscular

adj
  • Of or resembling twilight; dim. 

  • Active at or around dusk, dawn or twilight. 

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