mettle
Pronunciation: /ˈmɛt(ə)l/
noun

Phrases
-
be on one's mettle
- be ready or forced to do one’s best in a demanding situation: Saturday’s game will be a tricky one and we’ll have to be on our mettle from the start
-
put someone on their mettle
- (of a demanding situation) test someone’s ability to face difficulties: there were regular public meetings where local MPs were put on their mettle and remorselessly pilloried

Origin:
mid 16th century: specialized spelling (used for figurative senses) of metal