murmur vs roar

murmur

verb
  • To speak or make low, indistinguishable noise; to mumble, mutter. 

  • To say (something) indistinctly, to mutter. 

noun
  • The sound made by any condition which produces noisy, or turbulent, flow of blood through the heart. 

  • A muttered complaint or protest; the expression of dissatisfaction in a low muttering voice; any expression of complaint or discontent. 

  • Soft indistinct speech. 

  • Any low, indistinct sound, like that of running water. 

roar

verb
  • Generally, of inanimate objects etc., to make a loud resounding noise. 

  • Of animals (especially a lion), to make a loud deep noise. 

  • To make a loud noise in breathing, as horses do when they have a certain disease. 

  • To proceed vigorously. 

  • To be boisterous; to be disorderly. 

  • To cry aloud; to proclaim loudly. 

  • To laugh in a particularly loud manner. 

  • To make a loud, deep cry, especially from pain, anger, or other strong emotion. 

  • to cry 

noun
  • A loud resounding noise. 

  • A show of strength or character. 

  • The deep cry of the bull. 

  • A long, loud, deep shout, as of rage or laughter, made with the mouth wide open. 

  • The cry of the lion. 

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