challenge (noun)
1: a demanding or stimulating situation; "they reacted irrationally to the challenge of Russian power"
2: a call to engage in a contest or fight
3: questioning a statement and demanding an explanation; "his challenge of the assumption that Japan is still our enemy"
4: a formal objection to the selection of a particular person as a juror
5: a demand by a sentry for a password or identification
challenge
(verb)
1: take exception to; "She challenged his claims" [syn: dispute, gainsay]
2: issue a challenge to; "Fischer challenged Spassky to a match"
3: ask for identification; "The illegal immigrant was challenged by the border guard"
4: raise a formal objection in a court of law [syn: [[take exception]]]