doodle vs graffiti

doodle

noun
  • A small mindless sketch, etc. 

  • Penis. 

  • Any crossbreed of a poodle with a different breed of dog. 

verb
  • To draw or scribble aimlessly. 

  • To drone like a bagpipe. 

graffiti

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

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

verb
  • To mark a surface with such images. 

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