closeness vs covertness

closeness

noun
  • The state of being secretive 

  • The shortest path between two vertices in a graph 

  • The state of being close (all senses) 

  • The state of being friends 

  • The state of being mean or stingy 

covertness

noun
  • The characteristic of being covert. 

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