ductile vs stubborn

ductile

adj
  • Capable of being pulled or stretched into thin wire by mechanical force without breaking. 

  • Led easily; prone to follow. 

  • Molded easily into a new form. 

stubborn

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

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

noun
  • Stubbornness. 

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

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