step on vs subjugate

step on

verb
  • Used other than figuratively or idiomatically: see step, on. 

  • to adulterate a drug for the purpose of increasing its bulk, and therefore its profit; to dilute, cut. 

subjugate

verb
  • To forcibly impose obedience or servitude upon. 

adj
  • In a subjugated position. 

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