auxiliary vs grass-roots

auxiliary

noun
  • A person or group that acts in an auxiliary manner. 

  • An auxiliary verb. 

  • A marching band colorguard. 

  • A sailing vessel equipped with an engine. 

adj
  • Supplementary or subsidiary. 

  • Helping; giving assistance or support. 

  • Held in reserve for exceptional circumstances. 

  • Of a ship, having both sails and an engine. 

  • Relating to an auxiliary verb. 

grass-roots

How often have the words auxiliary and grass-roots occurred in a corpus of books? (source: Google Ngram Viewer )