sinister vs threatening

sinister

adj
  • Evil or seemingly evil; indicating lurking danger or harm. 

  • On the left side of a shield from the wearer's standpoint, and the right side to the viewer. 

  • Inauspicious, ominous, unlucky, illegitimate (as in bar sinister). 

threatening

adj
  • Presenting a threat, posing a likely risk of harm. 

  • Making threats, making statements about a willingness to cause harm. 

noun
  • An act of threatening; a threat. 

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