ironclad

[ adjective ahy-ern-klad; noun ahy-ern-klad ]

/ adjective ˈaɪ ərnˈklæd; noun ˈaɪ ərnˌklæd /

covered or cased with iron plates, as a ship for naval warfare; armor-plated.

very rigid or exacting; inflexible; unbreakable: an ironclad contract.

a wooden warship of the middle or late 19th century having iron or steel armor plating.

Origin of ironclad

First recorded in 1850–55; iron + clad¹

The Dallas case is breaking some of our ironclad assumptions.

The CDC Was Wrong About How to Stop Ebola |Kent Sepkowitz |October 1, 2014 |DAILY BEAST
But its now obvious the ironclad security guarantees they claimed to provide are perfectly hollow.

Ukraine Expects U.S. Military Help If War With Russia Starts |Jamie Dettmer |March 17, 2014 |DAILY BEAST
The other rule, which is just as ironclad, gave rise to their motto: “Blood In/Blood Out.”

Why I Fear the Aryan Brotherhood—and You Should, Too |Anonymous |April 1, 2013 |DAILY BEAST
What they need is a workable, ironclad, conflict-ending arrangement to allow them to live side-by-side in peace.

The Lessons of the Nakba |Ziad J. Asali |May 11, 2012 |DAILY BEAST

Ironclad vows like this tend to lock a nation into a position from which it cannot later retreat.

Obama’s ‘No Containment’ AIPAC Speech Made War With Iran Inevitable |Michael Tomasky |March 6, 2012 |DAILY BEAST
Robert designed and projected an ironclad battleship, the first one in the world.

The Age of Invention |Holland Thompson
The ironclad frigates and monitors of modern Spain have been almost all constructed in foreign dockyards.

Spain |Wentworth Webster
You might go so far as t' give that bellerin' ironclad a toot.'

Harbor Tales Down North |Norman Duncan
Bryce was skipper of the Fairy, an iron smack, which was known in the fleet as the Ironclad.

The Lively Poll |R.M. Ballantyne
I would as soon have a paper ship as an ironclad; only give me men to fight her!

A Short Life of Abraham Lincoln |John G. Nicolay

ironclad

covered or protected with iron an ironclad warship

inflexible; rigid an ironclad rule

not able to be assailed or contradicted an ironclad argument

a large wooden 19th-century warship with armoured plating