foxing vs graffiti

foxing

noun
  • The discoloration of printed material with brown marks. 

  • A band of material joining the upper of a shoe to the sole. 

  • Crafty or wily behavior. 

graffiti

noun
  • Informal inscriptions, figure drawings, etc., as opposed to official inscriptions. 

  • Drawings or words drawn on a surface in a public place, usually made without authorization. 

verb
  • To mark a surface with such images. 

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