Solid or certain; not able to be disputed or questioned; irrefutable.
Covered with iron, steel, or some metal; armor-plated.
Rigorous; severe; exacting.
Stubborn; inflexible.
An armor-plated warship, (especially) one preceding the invention of harveyized steel.
A metal-plated ship, vessel, or vehicle.
That cannot be ascertained; uncertain, unable to be determined or discovered.