properly the untamed, unconquerable:
I.as Subst. adamant, i. e. the hardest metal, prob. steel: metaph. of any thing unalterable, ἔπος ἐρέω ἀδάμαντι πελάσσας having fixed it firm as adamant, Orac. ap. Hdt.
2.the diamond, Theophr.
II.as adj., metaph., the inflexible, of Hades, Theocr.