adamantine
Americanadjective
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utterly unyielding or firm in attitude or opinion.
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too hard to cut, break, or pierce.
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like a diamond in luster.
adjective
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very hard; unbreakable or unyielding
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having the lustre of a diamond
Etymology
Origin of adamantine
First recorded in 1200–1250; Middle English, from Latin adamantinus, from Greek adamántinos adamant, -ine 1
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Although in her youth Catherine had imbibed Enlightenment views about the suffering of the common people, she was pragmatic enough to leave undisturbed the adamantine ways of the Russian countryside.
From The Wall Street Journal • Mar. 17, 2026
To love a Scorpio, then, is to fiercely protect their softness with the same shadowy ardor that they use to construct their inner adamantine fortresses.
From Los Angeles Times • Oct. 21, 2024
In this hardscrabble world, the embattled man must “form that solid and adamantine fibre which will endure long and serious attacks upon it,” lest he be “wholly emasculated.”
From The New Yorker • Mar. 21, 2017
“I’m very competitive,” she said, her tone adamantine.
From New York Times • May 27, 2016
“The haunting begins at midnight,” said the girl with the adamantine chin.
From "The Woman Warrior" by Maxine Hong Kingston
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.