/met"l/ , n.
1. courage and fortitude: a man of mettle.
2. disposition or temperament: a man of fine mettle.
3. on one's mettle , in the position of being incited to do one's best The loss of the first round put him on his mettle to win the match.
[ 1575-85; sp. var. of METAL, in metaphoric usages ]
Syn. 1. valor, pluck, vigor, ardor, nerve, fiber.