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