graffiti vs mottle

graffiti

verb
  • To mark a surface with such images. 

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. 

mottle

verb
  • To mark with blotches of different color, or shades of color, as if stained; to spot; to maculate. 

noun
  • A distinguishing blotch of color. 

  • A mottled coloration or pattern. 

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