averment vs negation

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. 

negation

noun
  • A proposition which is the contradictory of another proposition and which can be obtained from that other proposition by the appropriately placed addition/insertion of the word "not". (Or, in symbolic logic, by prepending that proposition with the symbol for the logical operator "not".) 

  • A denial or contradiction. 

  • The logical operation which obtains such (negated) propositions. 

  • The act of negating something. 

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