blur vs obscure

blur

verb
  • To make indistinct or hazy, to obscure or dim. 

  • To cause imperfection of vision in; to dim; to darken. 

  • To become indistinct. 

  • To transfer the input focus away from. 

  • To smear, stain or smudge. 

noun
  • Something that appears hazy or indistinct 

  • A smear, smudge or blot 

adj
  • In a state of doubt or confusion. 

obscure

verb
  • To render obscure; to darken; to make dim; to keep in the dark; to hide; to make less visible, intelligible, legible, glorious, beautiful, or illustrious. 

  • To hide, put out of sight etc. 

adj
  • Dark, faint or indistinct. 

  • Difficult to understand. 

  • Not well-known. 

  • Hidden, out of sight or inconspicuous. 

  • Unknown or uncertain; unclear. 

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