coal black vs swart

coal black

adj
  • Of an intensely black colour, like that of coal. 

noun
  • A black colour, like that of coal; charcoal. 

swart

adj
  • Black. 

  • Of a dark hue; moderately black; swarthy; tawny. 

verb
  • To make swart or tawny; blacken; tan. 

noun
  • Black or dark dyestuff. 

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