aggravating circumstance vs threat

aggravating circumstance

noun
  • A factor that increases the culpability or deleterious consequences of a wrongful act. 

threat

noun
  • An expression of intent to injure or punish another. 

  • A person or object that is regarded as a danger; a menace. 

  • An indication of potential or imminent danger. 

verb
  • To press; urge; compel. 

  • To use threats; act or speak menacingly; threaten. 

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