be on (one's) mettle

(redirected from be on mettle)
Also found in: Dictionary, Thesaurus, Legal.

be on (one's) mettle

To be determined to succeed and thus prove one's worth, often in a difficult or unpleasant situation. I know my employees think I'm too young to be their supervisor, so I have to be on my mettle every day at the office.
See also: mettle, on

be on your mettle

be ready or forced to prove your ability to cope well with a demanding situation.
See also: mettle, on