constraining vs steamroller

constraining

noun
  • The act by which something is constrained. 

steamroller

noun
  • Any seemingly irresistible force. 

  • Any heavy road roller. 

  • A pipe, used for smoking cannabis, open at both ends and having a bowl near one end; it rolls the smoke (steam). 

  • A steam-powered heavy road roller. 

verb
  • To level a road using a steamroller. 

  • To proceed ruthlessly against all opposition as if with an overwhelming force. 

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