Definition of "adamantine"

adamantine

/ˌæd.əˈmæn.taɪn/

adjective
comparative more adamantine, superlative most adamantine
1. Made of adamant, or having the qualities of adamant; incapable of being broken, dissolved, or penetrated.
  Quotations
  Him the Almighty PowerHurld headlong flaming from th' Ethereal SkieWith hideous ruine and combustion downTo bottomless perdition, there to dwellIn Adamantine Chains and penal Fire,Who durst defie th' Omnipotent to Arms.
  1667, John Milton, “Book I”, in Paradise Lost. […], London: […] [Samuel Simmons], […]; republished as Paradise Lost in Ten Books: […], London: Basil Montagu Pickering […], 1873, lines 44–49
  Snatch, snatch those gentle forms from war's alarms,And throw your adamantine shield around their shrinking charms.
  1827, Lydia Sigourney, Poems, Missolonghi, page 187
  For two hours they stand; Bouillé's sword glittering in his hand, adamantine resolution clouding his brows[.]
  1837, Thomas Carlyle, The French Revolution: A History […], volumes (please specify |volume=I to III), London: Chapman and Hall, (please specify the book or page number)
  Sex law is the most adamantine instrument of sexual stratification and erotic persecution.
  1984, Gayle Rubin, "Thinking Sex" in Carole S. Vance, Pleasure and Danger: Exploring Female Sexuality (Boston: Routledge and Kegan Paul), 267-319.
2. Like the diamond in hardness or luster.
noun
uncountable
1. Synonym of adamantium