continuative vs unperpetual

continuative

adj

  • Of or pertaining to continuation. 

  • durative. 

noun

  • a durative. 

  • Something that causes a continuation. 

unperpetual

adj

  • Not perpetual; impermanent. 

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