covert vs obvious

covert

adj
  • Under coverture. 

  • Secret, surreptitious, concealed. 

noun
  • A covering. 

  • A disguise. 

  • A feather that covers the bases of flight feathers. 

  • Area of thick undergrowth where animals hide. 

  • A hiding place. 

obvious

adj
  • Easily discovered, seen, or understood; self-explanatory. 

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