adj
ironclad
adj
1
So solid or certain that it cannot reasonably be disputed or broken.
"The contract came with an ironclad guarantee."
"She had an ironclad alibi for the night of the robbery."
noun
1
Historically, a warship protected by iron or steel armor plating.
"The battle between two ironclads changed naval warfare forever."
How to Use Ironclad
Learner’s notesIn plain EnglishExtremely solid and dependable — used mostly for agreements, alibis, or guarantees today.
Common pairings
ironclad contract
ironclad alibi
ironclad guarantee
Word Forms
more ironclad comparative, ironclads plural, most ironclad superlative
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The contract came with an _____ guarantee.
Etymology
From iron plus clad ("clothed, covered") — literally "covered in iron," originally describing armored warships.