An imaginary rock or mineral of impenetrable hardness; a name given to the diamond and other substances of extreme hardness.
impervious to pleas, persuasion, requests, reason
"he is adamant in his refusal to change his mind"
"Cynthia was inexorable; she would have none of him"
"an intransigent conservative opposed to every liberal tendency"
Firm; unshakeable; unyielding; determined.
The word "adamant" comes from the Latin adamās, which originally meant "hard as steel." This term was borrowed from Ancient Greek, where it described something invincible by combining a negative prefix with a root meaning "to tame."