ironclad
Americanadjective
-
covered or cased with iron plates, as a ship for naval warfare; armor-plated.
-
very rigid or exacting; inflexible; unbreakable.
an ironclad contract.
noun
adjective
-
covered or protected with iron
an ironclad warship
-
inflexible; rigid
an ironclad rule
-
not able to be assailed or contradicted
an ironclad argument
noun
Etymology
Origin of ironclad
Explanation
Something ironclad is either covered in iron for protection or protected in a different way. An ironclad guarantee can’t be broken or taken back. Originally, this word was very literal: an ironclad battleship was clad (covered) in iron. Since then, this word is more metaphorical, though it still applies to things you can trust. An ironclad contract is unbreakable. An ironclad promise can be believed wholeheartedly. If you were arrested on ironclad charges, you’re going to be found guilty.
Vocabulary lists containing ironclad
The American Civil War
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President Trump's First State of The Union Address (2018)
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Courage to Soar
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
It also reaffirms the UK and Poland's "ironclad commitment" to Nato and speaks of migrant smuggling being a "shared challenge requiring joint solutions".
From BBC • May 27, 2026
China has also invested billions into infrastructure projects in Pakistan as part of President Xi Jinping's Belt and Road initiative and the two governments call themselves "ironclad brothers."
From Barron's • Apr. 10, 2026
Nvidia’s next earnings report in November made it clear the $100 billion figure wasn’t exactly an ironclad commitment.
From MarketWatch • Feb. 1, 2026
The whole idea is that they are likelier to win the battle for public opinion, and thus the legislative fight, if their argument is clear, ironclad, impossible to refute.
From Slate • Oct. 1, 2025
Then, in 1973, a team of scientists from Duke University’s Maritime Laboratory found the historic ironclad.
From "Shipwrecked!" by Martin W. Sandler
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
