adamantine

[ ad-uh-man-teen, -tin, -tahyn ]

adjective

1. utterly unyielding or firm in attitude or opinion.
2. too hard to cut, break, or pierce.
3. like a diamond in luster.

adamantine

/ ˌædəˈmæntaɪn /

adjective

1. very hard; unbreakable or unyielding
2. having the lustre of a diamond

Word History and Origins

Origin of adamantine¹

First recorded in 1200–1250; Middle English, from Latin adamantinus, from Greek adamántinos adamant, -ine ¹