continuative vs imperfective

continuative

adj
  • Of or pertaining to continuation. 

  • durative. 

noun
  • a durative. 

  • Something that causes a continuation. 

imperfective

adj
  • Of, relating to or having the properties of the imperfective aspect. 

noun
  • The imperfective aspect; a verb having this aspect. 

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