ironclad

American  

[ahy-ern-klad, ahy-ern-klad] / ˈaɪ ərnˈklæd, ˈaɪ ərnˌklæd /

adjective

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

2. very rigid or exacting; inflexible; unbreakable.

   an ironclad contract.

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noun

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

ironclad British  

adjective

1. covered or protected with iron

   an ironclad warship

2. inflexible; rigid

   an ironclad rule

3. not able to be assailed or contradicted

   an ironclad argument

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noun

1. a large wooden 19th-century warship with armoured plating

Etymology

Origin of ironclad

First recorded in 1850–55; iron + clad ¹

Example Sentences

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

Even if bubble fears are misplaced—remember, statistical observations are just that, not ironclad predictions—this trend is still noteworthy.

From Barron's • Dec. 10, 2025

The American legal system, he says, is largely based on precedent, not ironclad statutes, leaving some wiggle room for questionable business practices.

From The Wall Street Journal • Oct. 2, 2025

But if they don’t include ironclad provisions outlawing impoundment under all circumstances, those concessions won’t be worth the paper they’re printed on.

From Slate • Sep. 10, 2025

“He always hinted that he had an ironclad reason for trusting Snape,” muttered Professor McGonagall, now dabbing at the corners of her leaking eyes with a tartan-edged handkerchief.

From "Harry Potter and the Half-Blood Prince" by J.K. Rowling

Related Words

• abiding
• definite
• inflexible
• unwavering