ad·​a·​man·​tine ˌa-də-ˈman-ˌtēn How to pronounce adamantine (audio)
: made of or having the quality of adamant
: rigidly firm : unyielding
adamantine discipline
: resembling the diamond in hardness or luster

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The Greek and Latin word for the hardest imaginable substance, whether applied to a legendary stone or an actual substance, such as diamond, was adamas. Latin poets used the term figuratively for things lasting, firm, or unbending, and the adjective adamantinus was applied in similar contexts. The English noun adamant (meaning "an unbreakable or extremely hard substance") as well as the adjective adamant ("inflexible" or "unyielding") came from adamas. Adamantine, however—which has such figurative uses as "rigid," "firm," and "unyielding"—came from adamantinus. Adamas is also the source of diamond. Diamas, the Latin term for diamond, is an alteration of adamas.

Examples of adamantine in a Sentence

the adamantine opposition of his parents to his marriage to a girl from a poor family
Recent Examples on the Web This poor little deer had to be sacrificed by your adamantine reviewer to show you how the new tool works. PCMAG, 30 May 2024 At the Guggenheim Bilbao, at Glenstone, at SF MoMA and in St. Louis — in so many places around the world — Serra’s adamantine sculptures act on you. Sebastian Smee, Washington Post, 27 Mar. 2024 She is known for her aphoristic precision and intense, adamantine paragraphs. Matthew Gavin Frank, Harper's Magazine, 21 Feb. 2022 So contrary to what Gordon suggests, effective teaching, as Weber saw it, involves much more than pitting students’ opinions against adamantine facts. Peter E. Gordon, The New York Review of Books, 19 Nov. 2020 Davosites are defined by their adamantine belief in economic and social liberalism and their position at the top of various global organisations. The Economist, 16 Nov. 2019 Every year The Rock is pre-painted a different color to prepare an adamantine canvas., 9 July 2019 Some of the time identity seems to be taken as an adamantine fact: a person’s identity as a woman or a member of an ethnic minority seems to trump all other considerations. The Economist, 19 June 2019 This gentle, tenacious, adamantine figure has been far too little known in the West—until now. Cynthia Haven, WSJ, 25 Jan. 2019

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'adamantine.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Middle English, borrowed from Anglo-French, borrowed from Latin adamantinus, borrowed from Greek adamántinos, derivative of adamant-, adámas adamant entry 2

First Known Use

13th century, in the meaning defined at sense 1

Time Traveler
The first known use of adamantine was in the 13th century


Dictionary Entries Near adamantine

Cite this Entry

“Adamantine.” Dictionary, Merriam-Webster, Accessed 16 Jun. 2024.

Kids Definition


ad·​a·​man·​tine ˌad-ə-ˈman-ˌtēn How to pronounce adamantine (audio)
: made of or having the quality of adamant

Medical Definition


ad·​a·​man·​tine ˌad-ə-ˈman-ˌtēn How to pronounce adamantine (audio) -ˌtīn How to pronounce adamantine (audio) -ˈmant-ᵊn How to pronounce adamantine (audio)
: characterized by extreme hardness or luster

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