adamant🔊

(said of people and their conviction) Firm; unshakeable; unyielding; determined.

(of an object) Very difficult to break, pierce, or cut.

An imaginary rock or mineral of impenetrable hardness; a name given to the diamond and other substances of extreme hardness.

An embodiment of impregnable hardness.

(archaic) A lodestone.

(obsolete or historical) A substance that neutralizes lodestones.