His fiscal discipline turned out to be flexible but, for better or worse, Mr Osborne's seems adamantine.

ECONOMIST: The Tories

Evert was emotionless on the court, gutting weaker-willed opponents with her adamantine demeanor.

FORBES: Chris Evert and Martina Navratilova: The Best Rivalry Ever?

What Mr Brown needs is to find a tone between adamantine denial and abject prostration, one that bolsters his authority rather than forfeiting it.

ECONOMIST: Bagehot