black man vs dusk

black man

noun
  • A male adult member of an ethnic group having dark pigmentation of the skin, typically of sub-Saharan African descent; or the appearance thereof. 

  • Used other than figuratively or idiomatically: see black, man. 

dusk

noun
  • A darkish colour. 

  • The condition of being dusky; duskiness 

  • A period of time at the end of day when the sun is below the horizon but before the full onset of night, especially the darker part of twilight. 

adj
  • Tending to darkness or blackness; moderately dark or black; dusky. 

verb
  • To begin to lose light or whiteness; to grow dusk. 

  • To make dusk. 

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