ironclad

1 of 2

adjective

iron·​clad ˈī(-ə)rn-ˈklad 

1

: sheathed in iron armor

—used especially of naval vessels

2

: so firm or secure as to be unbreakable: such as

a

: binding

an ironclad oath

b

: having no obvious weakness

an ironclad case against the defendant

ironclad

2 of 2

noun

iron·​clad ˈī(-ə)rn-ˌklad 

: an armored naval vessel especially of the mid to late 19th century

Examples of ironclad in a Sentence

Adjective

The company has an ironclad policy against revealing secrets to competitors.

He has an ironclad alibi.

Recent Examples on the Web

Adjective

Ossoff, Georgia's first Jewish senator, says his support for Israel is ironclad. — Sam Gringlas, NPR, 27 Aug. 2026

Watson, who continues to deny any wrongdoing, has not earned a dollar of his ironclad contract and hasn’t at all looked like an NFL quarterback, especially during that Saturday make-believe matchup against the Buffalo Bills. — Candace Buckner, New York Times, 25 Aug. 2026

Noun

Israel, for its part, enjoyed the most ironclad of American security guarantees. — Marc Lynch, Foreign Affairs, 18 Aug. 2026

The Confederate ironclad Tennessee patrolled the bay, and Fort Morgan and Fort Gaines stood sentry over the entrance. — Encyclopedia Britannica, 18 Aug. 2026

Word History

First Known Use

Adjective

circa 1847, in the meaning defined at sense 1

Noun

1862, in the meaning defined above

Rhymes for ironclad

• cephalad
• galahad
• libertad
• undergrad
• ad
• add
• bad
• brad
• cad
• clad
• dad
• fad

Kids Definition

ironclad

1 of 2 adjective

iron·​clad -ˈklad 

1

: covered by iron armor

2

: rigorous sense 1, exacting

ironclad laws

ironclad

2 of 2 noun

iron·​clad -ˌklad 

: an armored naval vessel