imply vs refrain

imply

verb
  • to hint; to insinuate; to suggest tacitly and avoid a direct statement 

  • to suggest by logical inference 

  • to have as a necessary consequence 

refrain

verb
  • To stop oneself from some action or interference; to abstain. 

  • To abstain from (food or drink). 

noun
  • The chorus or burden of a song repeated at the end of each verse or stanza. 

  • A much repeated comment, complaint, or saying. 

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