<p><strong>Adjective</strong></p><ul><li>covered or cased with iron plates, as a ship for naval warfare; armor-plated</li><li>very rigid or exacting; inflexible; unbreakable: an ironclad contract</li></ul><p><strong>Noun</strong></p><ul><li>a wooden warship of the middle or late 19th century having iron or steel armor plating</li></ul>