converb vs gerundive

converb

noun
  • A non-finite verb form that serves to express adverbial subordination. 

  • A verb with a stressed, separable prefix. 

gerundive

noun
  • a verbal adjective that describes obligation or necessity, equivalent in form to the future passive participle. 

  • a verbal adjective ending in -ing , also called a "present participle". 

adj
  • gerundial 

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