equivocation vs perseverance

equivocation

noun
  • A logical fallacy resulting from the use of multiple meanings of a single expression. 

  • The use of expressions susceptible of a double signification, possibly intentionally and with the aim of misleading. 

perseverance

noun
  • Continuing in a course of action without regard to discouragement, opposition or previous failure. 

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