challenge

I. verb (challenged; challenging) Etymology: Middle English chalengen to accuse, from Anglo-French chalenger, from Latin calumniari to accuse falsely, from calumnia calumny Date: 13th century transitive verb 1. to demand as due or deserved ; require <

an event that challenges explanation

> 2. to order to halt and prove identity <

the sentry challenged the stranger

> 3. to dispute especially as being unjust, invalid, or outmoded ; impugn <

new data that challenges old assumptions

> 4. to question formally the legality or legal qualifications of <

challenge a juror

> 5. a. to confront or defy boldly ; dare <

he challenged his critics to prove his guilt

> b. to call out to duel or combat c. to invite into competition <

he challenged his brother to a tennis match

> 6. to arouse or stimulate especially by presenting with difficulties <

she wants a job that will challenge her

> 7. to administer a physiological and especially an immunologic challenge to (an organism or cell) intransitive verb 1. to make or present a challenge 2. to take legal exception • challenger noun II. noun Date: 14th century 1. a. a summons that is often threatening, provocative, stimulating, or inciting; specifically a summons to a duel to answer an affront b. an invitation to compete in a sport 2. a. a calling to account or into question ; protest b. an exception taken to a juror before the juror is sworn c. a sentry's command to halt and prove identity d. a questioning of the right or validity of a vote or voter 3. a stimulating task or problem <

looking for new challenges

> 4. the act or process of provoking or testing physiological activity by exposure to a specific substance; especially a test of immunity by exposure to an antigen