mettle

The ability to meet a challenge or persevere under demanding circumstances; determination or resolve.

(on (one’s) mettle) Prepared to accept a challenge and do one’s best.

Same as metal.

Physical or moral constitution; material.

Natural tempera me ut; specifically, a masculine and ardent temperament; spirit; courage; ardor; enthusiasm.

Substance or quality of temperament; spirit, esp. as regards honor, courage, fortitude, ardor, etc.; disposition; — usually in a good sense.

to cause or incite one to use one’s best efforts.

A quality of endurance and courage.

Good temperament and character.

Metal; a metallic substance.