/ Dictionary / Index A adamantine: Meaning and Definition of Find definitions for: ad•a•man•tine Pronunciation: (ad"u-man't?n, -tin, -t?n), [key] ? adj. utterly unyielding or firm in attitude or opinion. too hard to cut, break, or pierce. like a diamond in luster. Random House Unabridged Dictionary, Copyright 1997, by Random House, Inc., on Infoplease. See also: adamantine (Thesaurus) adamantane Adamawa-Eastern Related Content Daily Word Quiz: ravenous Analogy of the Day: Today?s Analogy Spelling Bee: Today?s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language