roil vs roust

roil

verb
  • To annoy; to make angry; to throw into discord. 

  • To romp. 

  • To render turbid by stirring up the dregs or sediment of. 

  • To bubble, seethe. 

roust

verb
  • To harass, to treat in a rough way. 

  • to arrest 

  • to rout out of bed; to rouse 

  • to drive strongly 

noun
  • A strong tide or current, especially in a narrow channel. 

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