denigrate vs insult

denigrate

verb
  • To criticise so as to besmirch; traduce, disparage or defame. 

  • To treat as worthless; belittle, degrade or disparage. 

  • To blacken. 

insult

verb
  • To be insensitive, insolent, or rude to (somebody); to affront or demean (someone). 

noun
  • Something causing disease or injury to the body or bodily processes; the injury so caused. 

  • Something that causes offence (for example, by being of an unacceptable quality). 

  • Action or form of speech deliberately intended to be rude; (countable) a particular act or statement having this effect. 

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