challenge challenge /ˈtʃæləndʒ/

noun

1. () A demanding or stimulating situation  ( challenge )
   a demanding or stimulating situation
    They reacted irrationally to the challenge of Russian power
   they reacted irrationally to the challenge of Russian power
   
2. () A call to engage in a contest or fight  ( challenge )
   a call to engage in a contest or fight
   
3. () Questioning a statement and demanding an explanation  ( challenge )
   questioning a statement and demanding an explanation
    His challenge of the assumption that Japan is still our enemy
   his challenge of the assumption that Japan is still our enemy
   
4. A demand by a sentry for a password or identification  ( challenge )
   a demand by a sentry for a password or identification
   
5. A formal objection to the selection of a particular person as a juror  ( challenge )
   a formal objection to the selection of a particular person as a juror
   

verb

1. () Take exception to  ( gainsay , dispute , challenge )
   take exception to
    She challenged his claims
   She challenged his claims
   
2. () Issue a challenge to  ( challenge )
   issue a challenge to
    Fischer challenged Spassky to a match
   Fischer challenged Spassky to a match
   
3. () (law) raise a formal objection in a court of law  ( challenge , take exception )
   (law) raise a formal objection in a court of law
   
4. () Ask for identification  ( challenge )
   ask for identification
    The illegal immigrant was challenged by the border guard
   The illegal immigrant was challenged by the border guard