remain vs tough

remain

verb
  • To continue in a state of being. 

  • To await; to be left to. 

  • To continue unchanged in place, form, or condition, or undiminished in quantity; to abide; to stay; to endure; to last. 

  • To be left after a number or quantity has been subtracted or cut off; to be left as not included or comprised. 

  • To stay after others or other parts have been removed or otherwise disappeared. 

noun
  • That which is left; relic; remainder. 

  • That which is left of a human being after the life is gone; relics; a dead body. 

  • Posthumous works or productions, especially literary works. 

tough

verb
  • To endure. 

  • To toughen. 

intj
  • Used to indicate lack of sympathy 

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. 

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