What made you decide to look hard? Please let us know where you read or heard it (including the quote if possible). See the full definition of Ironclad in the dictionary of English language learners “Ironclad”. Merriam-Webster.com Dictionary, Merriam-Webster, www.merriam-webster.com/dictionary/ironclad. Retrieved December 2, 2020.Nglish: Translation of Ironclad for Spanish speakers These sample sentences are automatically selected from various online information sources to reflect the current use of the word “Ironclad”. The opinions expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us your feedback. Britannica.com: Encyclopedia article on Ironclad….