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

For a time, the once ironclad dominance of men – especially White men – in the corporate boardroom appeared to be slipping. —Jessica Guynn, USA Today, 23 Oct. 2025

Over the course of the 21st century, several mutual defense pacts that looked ironclad on paper have collapsed under fire. —Omar Al-Ubaydli, semafor.com, 8 Oct. 2025

Noun

One ironclad truism about sports is that all streaks eventually come to an end. —Pete Grathoff, Kansas City Star, 2 Oct. 2025

And on security, Ukraine is seeking ironclad guarantees against Russian aggression in the future, including Western peacekeeping troops on the ground. —Shane Croucher, MSNBC Newsweek, 8 Sep. 2025

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