sloe vs swart

sloe

noun
  • The small, astringent, wild fruit of the blackthorn (Prunus spinosa). 

  • The tree Prunus spinosa. 

  • Any of various other plants of the genus Prunus, as a shrub or small tree, Prunus alleghaniensis, bearing dark-purple fruit. 

swart

noun
  • Black or dark dyestuff. 

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

  • Black. 

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

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