Noun

(-)

A quality of endurance and courage.

* 360 BCE , , Book VIII.

In the succeeding generation rulers will be appointed who have lost the guardian power of testing the metal of your different races, which, like Hesiod's, are of gold and silver and brass and iron.

* 1599 , '', act iv, scene 8 (''First Folio ed.)

By this Day and this Light, the fellow ha's mettell enough in his belly.

* 2001 , Harry J. Alexandrowicz, Testing your Mettle: Tough Problems and Real-world Solutions for Middle and High School Teachers , page xiii

Please read on and discover the issues in education that test the mettle of those who experience this world every day.

Good temperament and character.

* 1868 , , Bleak House

The arrival of this unexpected heir soon taking wind in the court, still makes good for the Sol, and keeps the court upon its mettle .

(obsolete) Metal; a metallic substance.

* 1837 , Robert Burton, The Anatomy of Melancholy , page 78

They have neither gold nor silver of their own, wine nor oyl, or scarce any corn growing in those United Provinces, little or no wood, tin, lead, iron, silk, wooll, any stuff almost, or mettle ; and yet Hungary, Transilvania, that brag of their mines, fertile England, cannot compare with them.

Noun

(en noun)

a state of being belligerent

* {{quote-news, year=2013, date=April 9, author=Andrei Lankov, title=Stay Cool. Call North Korea’s Bluff., work=New York Times citation

, passage=A closer look at North Korean history reveals what Pyongyang’s leaders really want their near-farcical belligerence to achieve — a reminder to the world that North Korea exists, and an impression abroad that its leaders are irrational and unpredictable. }}