ironclad vs irresistible

ironclad

adj
  • Stubborn; inflexible. 

  • Solid or certain; not able to be disputed or questioned; irrefutable. 

  • Covered with iron, steel, or some metal; armor-plated. 

  • Rigorous; severe; exacting. 

noun
  • An armor-plated warship, (especially) one preceding the invention of harveyized steel. 

  • A metal-plated ship, vessel, or vehicle. 

irresistible

adj
  • Impossible to resist. 

  • Compellingly attractive. 

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