boulder vs grime

boulder

verb
  • To engage in bouldering. 

noun
  • A particle greater than 256 mm in diameter, following the Wentworth scale 

  • A large marble, in children's games. 

  • A session of bouldering; involvement in bouldering. 

  • A large mass of stone detached from the surrounding land. 

grime

verb
  • To begrime; to cake with dirt. 

noun
  • Dirt, grease, soot, etc. that is ingrained and difficult to remove. 

  • A genre of urban music that emerged in London, England, in the early 2000s, primarily a development of UK garage, dancehall, and hip hop. 

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