frighteningly vs idiosyncratically

frighteningly

adv
  • In a frightening or terrifying manner. 

  • Very; beyond usual expectation so as to cause surprise or concern. 

idiosyncratically

adv
  • In an idiosyncratic manner. 

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