bolstering vs fuel

bolstering

noun
  • The act by which something is bolstered; support. 

fuel

noun
  • Something that stimulates, encourages or maintains an action. 

  • Substance that provides nourishment for a living organism; food. 

  • Substance consumed to provide energy through combustion, or through chemical or nuclear reaction. 

verb
  • To exacerbate, to cause to grow or become greater. 

  • To provide with fuel. 

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