foment vs ignite

foment

verb
  • To incite or cause troublesome acts; to encourage; to instigate. 

  • To apply a poultice to; to bathe with a cloth or sponge. 

noun
  • Fomentation. 

ignite

verb
  • to spark off (something), to trigger 

  • to commence burning. 

  • to set fire to (something), to light (something) 

  • To subject to the action of intense heat; to heat strongly; often said of incombustible or infusible substances. 

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