assertion vs averment

assertion

noun
  • The act of asserting; positive declaration or averment. 

  • A statement in a program asserting a condition expected to be true at a particular point, used in debugging. 

  • A statement or declaration which lacks support or evidence. 

  • Maintenance; vindication 

  • Something which is asserted; a declaration; a statement asserted. 

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. 

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