covert baron vs ulterior

covert baron

adj
  • Covert, under coverture; married. 

ulterior

adj
  • Being intentionally concealed so as to deceive. 

  • Situated beyond, or on the farther side. 

  • Beyond what is obvious or evident. 

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