thug vs tough

thug

noun
  • Someone with an intimidating and unseemly appearance and mannerisms, who treats others violently and roughly, often for hire. 

  • One of a band of assassins formerly active in northern India who worshipped Kali and offered their victims to her. 

  • One who, usually as a result of social disadvantage, has turned to committing crimes (e.g. selling drugs, robbery, assault, etc.) to make a living; a gangsta. 

  • An over-vigorous plant that spreads and dominates the flowerbed. 

  • A punk; a hoodlum; a hooligan. 

  • A wooden bat used in the game of miniten, fitting around the player's hand. 

verb
  • To commit acts of thuggery, to live the life of a thug, or to dress and act in a manner reminiscent of someone who does. 

tough

noun
  • A person who obtains things by force; a thug or bully. 

adj
  • Harsh or severe. 

  • Difficult or demanding. 

  • Stubborn or persistent; capable of stubbornness or persistence. 

  • Strong and resilient; sturdy. 

  • Undergoing plastic deformation before breaking. 

  • Difficult to cut or chew. 

  • Rugged or physically hardy. 

  • Rowdy or rough. 

intj
  • Used to indicate lack of sympathy 

verb
  • To endure. 

  • To toughen. 

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