adusk vs obfuscous

adusk

adj

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

adv

  • At dusk; in the dusk or twilight. 

obfuscous

adj

  • dark; obscure; shadowy 

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