averment vs nullification

averment

noun
  • The act of averring, or that which is averred; positive assertion. 

  • verification; establishment by evidence. 

  • A positive statement of facts; an allegation; an offer to justify or prove what is alleged. 

nullification

noun
  • The nullification crisis in U.S. history, confrontation between the state of South Carolina and the federal government in 1832–33 over the former's attempt to declare null and void within the state the federal Tariffs of 1828 and 1832. 

  • Surgical removal of genitals (and sometimes nipples) as a form of body modification; a person who has undergone this surgery is a nullo. 

  • The act of nullifying; a rendering void and of no effect, or no legal effect. 

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