hush-hush vs truthful

hush-hush

noun
  • secrecy; covert operation 

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

truthful

adj
  • Honest, and always telling the truth. 

  • Accurately depicting what is real. 

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