discouraging vs stubborn

discouraging

adj
  • that causes discouragement 

noun
  • discouragement 

stubborn

adj
  • Refusing to move or to change one's opinion; obstinate; firmly resisting; persistent in doing something. 

  • Of materials: physically stiff and inflexible; not easily melted or worked. 

noun
  • Stubbornness. 

  • A disease of citrus trees characterized by stunted growth and misshapen fruit, caused by Spiroplasma citri. 

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