clandestine vs covert baron

clandestine

adj
  • Done or kept in secret, sometimes to conceal an illicit or improper purpose. 

  • Not recognized as a regular member. 

covert baron

adj
  • Covert, under coverture; married. 

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