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