illuminate vs obscure

illuminate

verb
  • To glow; to light up. 

  • To be exposed to light. 

  • To shine light on something. 

  • To decorate the page of a manuscript book with ornamental designs. 

  • To decorate something with lights. 

  • To clarify or make something understandable. 

  • To make spectacular. 

  • To direct a radar beam toward. 

noun
  • Someone thought to have an unusual degree of enlightenment. 

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 illuminate and obscure occurred in a corpus of books? (source: Google Ngram Viewer )