Having the hardness or strength of adamant; = "adamantine".
Origin
Late 17th century; earliest use found in John Milton (1608–1674), poet and polemicist. From classical Latin adamantēus of adamant (as typifying hardness; from adamant-, adamās + -eus: see -eous) + -an.
Definition of adamantean in US English:
adamantean
adjectiveˌadəmanˈtɪən
rare
Having the hardness or strength of adamant; = "adamantine".
Origin
Late 17th century; earliest use found in John Milton (1608–1674), poet and polemicist. From classical Latin adamantēus of adamant (as typifying hardness; from adamant-, adamās + -eus: see -eous) + -an.