adamantine

American  

[ad-uh-man-teen, -tin, -tahyn] / ˌæd əˈmæn tin, -tɪn, -taɪn /

adjective

1. utterly unyielding or firm in attitude or opinion.

2. too hard to cut, break, or pierce.

3. like a diamond in luster.

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adamantine British  

/ ˌædəˈmæntaɪn /

adjective

1. very hard; unbreakable or unyielding

2. having the lustre of a diamond

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Etymology

Origin of adamantine

First recorded in 1200–1250; Middle English, from Latin adamantinus, from Greek adamántinos see adamant, -ine ¹

Explanation

Something adamantine is unbreakable. Adamantine is often used in a figurative way. If you’re bound by adamantine chains, get comfy because you’re not breaking free! When someone is adamant, the person won't budge or yield. Anything adamantine is pretty much unbreakable and invulnerable. Adamantine substances also tend to be bright and shiny like diamonds. When used figuratively, adamantine can describe something unbreakable, like the adamantine will of a marathon runner.

Example Sentences

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

He’s since backed off a bit from his adamantine opposition, but the core of his position was concern that the measure would add to inflation.

From Los Angeles Times • Dec. 26, 2021

She arrived in the United States from India in the early 1980s, armed with a jet-black braid that fell down her back, dreams of dental school and an adamantine sense of determination.

From Washington Post • Jan. 24, 2019

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

“The haunting begins at midnight,” said the girl with the adamantine chin.

From "The Woman Warrior" by Maxine Hong Kingston