mild vs tough

mild

adj
  • Of only moderate severity; not strict. 

  • Not sharp or bitter; not strong in flavor. 

  • Not serious or dangerous. 

  • Moderately warm, especially less cold than expected. 

  • Gentle and not easily angered. 

  • Not overly felt or seriously intended. 

  • Acting gently and without causing harm. 

noun
  • A relatively low-gravity beer, often with a dark colour; mild ale 

tough

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. 

verb
  • To endure. 

  • To toughen. 

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

intj
  • Used to indicate lack of sympathy 

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