adj.
Pronunciation: ˌ a-d ə - ' man- ˌ t ē n, - ˌ t ī n, - ' man-t ə n
Function: adjective
Etymology: Middle English, from Latin adamantinus, from Greek adamantinos, from adamant-, adamas
Date: 13th century
1 : made of or having the quality of adamant
2 : rigidly firm : UNYIELDING < adamantine discipline>
3 : resembling the diamond in hardness or luster