aspersion vs graffiti

aspersion

noun
  • slander, calumny 

  • An attack on somebody's reputation or good name, often in the phrase to cast aspersions upon…. 

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 aspersion and graffiti occurred in a corpus of books? (source: Google Ngram Viewer )