concealment vs covert

concealment

noun
  • The condition of being hidden or concealed. 

  • The practice of keeping secrets. 

  • protection from observation or surveillance. 

covert

noun
  • A hiding place. 

  • A covering. 

  • A disguise. 

  • A feather that covers the bases of flight feathers. 

  • Area of thick undergrowth where animals hide. 

adj
  • Under coverture. 

  • Secret, surreptitious, concealed. 

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