iron·​clad | \ˈī(-ə)rn-ˈklad \

Definition of ironclad 

(Entry 1 of 2)

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


iron·​clad | \ˈī(-ə)rn-ˌklad \

Definition of ironclad (Entry 2 of 2)

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

Examples of ironclad in a Sentence


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

Recent Examples on the Web: Adjective

Although someone like Attorney General Jeff Sessions may have a credible argument that his denials of contact with Russians were the results of misunderstandings, Stone's and Caputo's denials were ironclad. Aaron Blake, Washington Post, "Roger Stone’s and Michael Caputo’s damningly false denials of contact with Russians," 18 June 2018 And the thing that came to my mind is, what would a story be like if the evidence that somebody committed a horrible crime was ironclad. CBS News, "Stephen King on "The Outsider" and where his ideas come from," 22 May 2018 While new, young designers constantly break out, the ranks of high fashion are historically ironclad. Elizabeth Raiss,, "Why Do We Treat A Fashion Designer Leaving A Brand Like Someone Dying?," 14 June 2018 This is why previous U.S. presidents have held off on recognition, pending an ironclad deal. Trudy Rubin,, "Trump-Kim summit: What to watch for when they meet in Singapore | Trudy Rubin," 6 June 2018 The rating is on par with those given by Moody’s Investors Service and Fitch Ratings to the U.S., and means that the country’s credit is ironclad, with default risk basically nonexistent. Gunjan Banerji, WSJ, "Kroll Bond Rating Agency Pushes Into Sovereign Debt," 28 Mar. 2018 The truest and worst thing about him is his ironclad sense of victimhood. Xavier Legrand, New York Times, "Review: In ‘Custody,’ a Father Terrorizes His Family," 27 June 2018 So Puma's really just following an ironclad rule of modern celebrity: When in doubt, follow Rihanna. Cam Wolf, GQ, "Jay-Z Named Head of Puma’s Relaunched Basketball Division," 19 June 2018 The professor also had certain ironclad rules about how speeches should be presented. Scott Fowler, charlotteobserver, "A Woody Durham story you don't know: Why UNC broadcaster made a B in speech class. | Charlotte Observer," 30 Mar. 2018

Recent Examples on the Web: Noun

During the Civil War, Eads won a contract to build Union ironclads. Mike Scott,, "Meet the man who tamed the Mississippi -- and saved the port of New Oreans," 1 May 2018 In 1862, during the Civil War, the ironclads USS Monitor and CSS Virginia (formerly USS Merrimac) clashed for five hours to a draw at Hampton Roads, Va., "This day in history," 9 Mar. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'ironclad.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of ironclad


circa 1847, in the meaning defined at sense 1


1862, in the meaning defined above

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Statistics for ironclad

Last Updated

25 Sep 2018

Look-up Popularity

Time Traveler for ironclad

The first known use of ironclad was circa 1847

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English Language Learners Definition of ironclad

: not able to be changed

: too strong to be doubted or questioned

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