iron·​clad | \ ˈī(-ə)rn-ˈklad How to pronounce ironclad (audio) \

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 How to pronounce ironclad (audio) \

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

Adjective The company has an ironclad policy against revealing secrets to competitors. He has an ironclad alibi.
Recent Examples on the Web: Adjective And, as humans are not omniscient, and the law of unintended consequences is ironclad, there may well be other unexpected costs. Jennifer Frazer, Scientific American, "Mining Rare-Earth Elements from...Fossilized Fish???," 21 Sep. 2020 One of the underrated differences between Biden and Sanders is that the former Senator built his reputation on transactional exchanges in Washington, while the latter built his on ironclad principles. Libby Watson, The New Republic, "Health Care Reform Is Being Slashed Into Oblivion," 21 Aug. 2020 Despite their origins in the region, though, the locks themselves weren’t always ironclad: One of the two recovered from Lair survived only as a broken bolt. Katherine J. Wu, Smithsonian Magazine, "Medieval Padlock Hints at Prosperity of Scotland’s Pictish Farmers," 15 Jan. 2020 To that end, a document need not be ironclad to intimidate potential plaintiffs. Tim Sullivan, The Courier-Journal, "Attorneys: U of L's 'binding' COVID-19 liability waivers for athletes may not be enforceable," 3 Aug. 2020 With their emotionally taxing plots and weepy protagonists, the best tearjerkers on Netflix have the ability to unlock even the most ironclad tear ducts. Christopher Rosa, Glamour, "The Best Tearjerkers on Netflix for When You Just Need a Good Cry," 3 Aug. 2020 Trump says it’s too early to make such an ironclad guarantee. Will Weissert, The Denver Post, "Trump not ready to commit to 2020 election results if he loses," 19 July 2020 But the consensus was overwhelming that, even without ironclad proof, Trump should have already issued forceful warnings. Todd J. Gillman, Dallas News, "Trump’s ongoing silence on Russia bounty allegations rebuked by Texans McCaul and Castro," 9 July 2020 There remains doubt, of course, about how ironclad the NBA’s return really is. oregonlive, "With Zach Collins’ ‘long and boring’ shoulder rehab behind him, Portland Trail Blazers forward excited for NBA restart and ‘championship’ chase," 17 June 2020 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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Time Traveler for ironclad

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The first known use of ironclad was circa 1847

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Last Updated

28 Sep 2020

Cite this Entry

“Ironclad.” Dictionary, Merriam-Webster, Accessed 1 Oct. 2020.

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More Definitions for ironclad


How to pronounce ironclad (audio)

English Language Learners Definition of ironclad

: not able to be changed
: too strong to be doubted or questioned

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