confirmed vs ironclad

confirmed

adj
  • having a settled habit; inveterate or habitual 

  • having received the rite of confirmation 

  • verified or ratified 

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. 

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