mugger vs ruffian

mugger

noun
  • A person who assaults and robs others, especially in a public place. 

  • A large crocodile, Crocodylus palustris, of southwest Asia, having a very broad wrinkled snout. 

  • A person who makes exaggerated faces, as a performance; a gurner. 

ruffian

noun
  • A scoundrel, rascal, or unprincipled, deceitful, brutal and unreliable person. 

verb
  • To play the ruffian; to rage; to raise tumult. 

adj
  • Brutal; cruel; savagely boisterous; murderous. 

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