percolate vs refrain

percolate

verb
  • To drain or seep through a porous substance. 

  • To pass a liquid through a porous substance; to filter. 

  • To make (coffee) in a percolator. 

  • To spread slowly or gradually; to slowly become noticed or realised. 

noun
  • A liquid that has been percolated. 

refrain

verb
  • To abstain from (food or drink). 

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

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 percolate and refrain occurred in a corpus of books? (source: Google Ngram Viewer )