This adjective describes something or someone that is unyielding, inflexible or unbreakable... or very adamant. This is from the Latin word adamanitus, which means "hard as steel." Peter Oborne of the Daily Telegraph describes the late Baroness Thatcher thus: "The magnificence of Thatcher was her adamantine refusal to accept the conventional wisdom of her age." (Emphasis mine.) And this woman, hard as steel, will not be forgotten for quite sometime. If the United States elects a woman into the office of President, she will have to be as strong as Britain's only female prime minister. It is not a job for wilting flowers.
Margaret Thatcher on the cover of Time Magazine
Bernard Bujold - LeStudio1