1.Definition: a call to engage in a contest or fight

Category: General

2.Definition: a demand by a sentry for a password or identification

Category: General

3.Definition: a demanding or stimulating situation

"They reacted irrationally to the challenge of Russian power"

Category: General

4.Definition: a formal objection to the selection of a particular person as a juror

Category: General

5.Definition: questioning a statement and demanding an explanation

"His challenge of the assumption that Japan is still our enemy"

Category: General