inefficient vs tough

inefficient

adj
  • Incapable of, or indisposed to, effective action; habitually slack or unproductive; effecting little or nothing 

  • Not efficient; not producing the effect intended or desired; inefficacious 

noun
  • A person who cannot or does not work efficiently. 

tough

adj
  • Stubborn or persistent; capable of stubbornness or persistence. 

  • Harsh or severe. 

  • Difficult or demanding. 

  • Strong and resilient; sturdy. 

  • Undergoing plastic deformation before breaking. 

  • Difficult to cut or chew. 

  • Rugged or physically hardy. 

  • Rowdy or rough. 

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

verb
  • To endure. 

  • To toughen. 

intj
  • Used to indicate lack of sympathy 

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