covert baron vs hush-hush

covert baron

adj

  • Covert, under coverture; married. 

hush-hush

adj

  • Secret, not spoken of (or spoken of only in hushed whispers between insiders). 

noun

  • secrecy; covert operation 

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