Definition of "adamant"

Broiles and Kirkley were adamant about getting out of the lawsuit, but Mike and Dee were equally adamant about not wanting to sign a letter of apology

2002, Charles Moncrief, Wildcatters: The True Story of how Conspiracy, Greed and the IRS ..., page 195

Johan is determined to play the field and adamant about never committing.

2006, Cara E. C. Vermaak, Confessions of the Dyslexic Virgin, page 275

What good would such foolishness do a mountain man? But Pa had been adamant. Just as he'd been adamant about their reading, writing, numbers, geography, and languages. Just as he'd been adamant about using proper grammar

2010, Deeanne Gist, Maid to Match, page 94

Unprotected matter, however adamant, would have been ground to dust ages ago.

1956, Arthur C. Clarke, The City and the Stars, page 34

This then is and alwayes hath ben the fashion of Worldlinges, & reprobate persons, to harden their hartes as an adamant stone, against anye thinge that shalbe tolde the for amendement of their lives, and for the savinge of their soules.

1582, Robert Parsons, chapter 8, in The first booke of the Christian exercise, appertayning to resolution‎, G. Flinton

As an adamant harder than flint have I made thy forehead …

1611, King James Translators, Ezekiel 3:9

But this was a finale she ever avoided: an offer, like the rock of adamant in Sinbad's voyages, finishes the attraction by destroying the vessel;...

1831, L[etitia] E[lizabeth] L[andon], chapter XV, in Romance and Reality. […], volume I, London: Henry Colburn and Richard Bentley, […], page 162

Actual life might seem to her so real that she could not detect the union of shadow and adamant that men call poetry.

1907, E.M. Forster, The Longest Journey, Part I, XV

You draw me, you hard-hearted adamant:But yet you draw not iron, for all my heartIs true as steel. Leave you your power to draw,And I shall have no power to follow you.

c. 1595–1596 (date written), William Shakespeare, “A Midsommer Nights Dreame”, in Mr. William Shakespeares Comedies, Histories, & Tragedies: Published According to the True Originall Copies (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, (please specify the act number in uppercase Roman numerals, and the scene number in lowercase Roman numerals)

An Adamant hinders the attractive vertue, as also Garlick rubbed on the Magnet; for its attractive faculty is not so valid, but it may be easily deluded, obscured, and superated […]

1657 , Jean de Renou, translated by Richard Tomlinson, A Medicinal Dispensatory […], page 418

But we know from book 37 of the Natural History that adamant works on magnets in exactly the same way that garlic does: robbing them of their power to attract.

2012, Daryn Lehoux, What Did the Romans Knows? An Inquiry into Science and Worldmaking, page 139