n. & v.
n. 1 a a summons to take part in a contest or a trial of strength etc., esp. to a duel. b a summons to prove or justify something. 2 a demanding or difficult task (rose to the challenge of the new job). 3 Law an objection made to a jury member. 4 a call to respond, esp. a sentry's call for a password etc. 5 an invitation to a sporting contest, esp. one issued to a reigning champion. 6 Med. a test of immunity after immunization treatment.
v.tr. 1 (often foll. by to + infin.) a invite to take part in a contest, game, debate, duel, etc. b invite to prove or justify something. 2 dispute, deny (I challenge that remark). 3 a stretch, stimulate (challenges him to produce his best). b (as challenging adj.) demanding; stimulatingly difficult. 4 (of a sentry) call to respond. 5 claim (attention, etc.). 6 Law object to (a jury member, evidence, etc.). 7 Med. test by a challenge. challengeable adj. challenger n.
[ ME f. OF c(h)alenge, c(h)alenger f. L calumnia calumniari calumny ]