challenge
verb chal·lenge \ ˈcha-lənj \
challenged; challenging
transitive verb
1 : to dispute especially as being unjust, invalid, or outmoded : impugn new data that challenges old assumptions
2 a : to confront or defy boldly : dare he challenged his critics to prove his guilt
b : to call out to duel or combat challenged his rival to a duel
c : to invite into competition he challenged his brother to a tennis match
3 : to question formally the legality or legal qualifications of challenge a juror
4 : to arouse or stimulate especially by presenting with difficulties she wants a job that will challenge her
5 : to order to halt and prove identity the sentry challenged the stranger
6 : to demand as due or deserved : require an event that challenges explanation
7 : to administer a physiological (see physiological 2) and especially an immunologic challenge to (an organism or cell)
intransitive verb
1 : to make or present a challenge
when the appropriate moment challenged, he was capable of … leadership —C. H. Driver
2 : to take legal exception
— challenger noun
— challengeable play \ˈcha-lən-jə-bəl\ adjective