black man vs slate gray

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. 

slate gray

noun
  • A dark bluish grey colour. 

adj
  • Of a dark bluish grey colour. 

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