'Mettle' definitions:

Definition of 'mettle'

From: WordNet
noun
The courage to carry on; "he kept fighting on pure spunk"; "you haven't got the heart for baseball" [syn: heart, mettle, nerve, spunk]

Definition of 'Mettle'

From: GCIDE
  • Mettle \Met"tle\, n. [E. metal, used in a tropical sense in allusion to the temper of the metal of a sword blade. See Metal.] Substance or quality of temperament; spirit, esp. as regards honor, courage, fortitude, ardor, etc.; disposition; -- usually in a good sense; as, to test a person's mettle. [1913 Webster]
  • A certain critical hour which shall . . . try what mettle his heart is made of. --South. [1913 Webster]
  • Gentlemen of brave mettle. --Shak. [1913 Webster]
  • The winged courser, like a generous horse, Shows most true mettle when you check his course. --Pope. [1913 Webster]
  • To put one one's mettle, to cause or incite one to use one's best efforts. [1913 Webster]