tenacious vs tough

tenacious

adj
  • Clinging to an object or surface; adhesive. 

  • Unwilling to yield or give up; dogged. 

  • Having a good memory; retentive. 

  • Holding together; cohesive. 

tough

adj
  • Undergoing plastic deformation before breaking. 

  • Harsh or severe. 

  • Difficult or demanding. 

  • Stubborn or persistent; capable of stubbornness or persistence. 

  • Strong and resilient; sturdy. 

  • Difficult to cut or chew. 

  • Rugged or physically hardy. 

  • Rowdy or rough. 

verb
  • To endure. 

  • To toughen. 

intj
  • Used to indicate lack of sympathy 

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

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