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

Did you know?

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.

Example Sentences

the adamantine opposition of his parents to his marriage to a girl from a poor family
Recent Examples on the Web She is known for her aphoristic precision and intense, adamantine paragraphs. Claire Messud, Harper’s Magazine , 18 Jan. 2022 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 But not even adamantine willpower could overcome the exhaustion that Rihanna was feeling in that moment. Chioma Nnadi, Vogue, 3 May 2018 But Navalny, with adamantine determination and a canny use of social media, has spread his anti-corruption campaign deep into the provinces. Washington Post, 25 Oct. 2017 Harrison’s music traverses a huge stylistic range, from adamantine dissonance to melodies of homespun sweetness. Alex Ross, The New Yorker, 14 Apr. 2017 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'adamantine.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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 5 Dec. 2022.

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

More from Merriam-Webster on adamantine

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

The Great British Vocabulary Quiz

  • union jack speech bubble
  • Named after Sir Robert Peel, what are British police called?
Spell It

Hear a word and type it out. How many can you get right?

Universal Daily Crossword

A daily challenge for crossword fanatics.