Adamant1. (n.) Unyielding in opinion; also a stone or diamond perceived to be of impenetrable hardness; a name given to the diamond and other substances of extreme hardness; but in modern mineralogy it has no technical signification. It is now a rhetorical or poetical name for the embodiment of impenetrable hardness.
2. (n.) Lodestone; magnet.
Thesaurus Entries
adamantine, at a standstill, cast-iron, dour, firm, flintlike, flinty, frozen, granitelike, granitic, grim, hard, hard-core, immobile, immotile, immotive, immovable, immutable, implacable, impliable, inductile, inelastic, inexorable, inextensible, inextensile, inextensional, inflexible, intractable, intractile, intransigent, iron, irreconcilable, irremovable, irresilient, lithic, marblelike, nonelastic, nonstretchable, obdurate, pat, petrified, petrogenic, relentless, rigid, rigorous, rock, rock-ribbed, slaty, standpat, stationary, steely, stern, stiff, stone, stubborn, unaffected, unalterable, unbending, unchangeable, uncompromising, unextendible, unextensible, unflexible, ungiving, unlimber, unmalleable, unmovable, unmoved, unmoving, unpliable, unpliant, unrelenting, unswayable, untractable, unyielding