clandestinely vs in petto

clandestinely

adv
  • In a secret or covert manner. 

  • In an illicit way, i.e. not permitted by the law or regulations. 

in petto

adv
  • Privately, in secret. 

adj
  • Secret, private. 

  • Designated as a cardinal but not yet announced. 

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