Verb a number of doctors are challenging the studys claims the new lawsuit challenges the lower courts decision shes been challenged on her handling of the problem none of them were willing to challenge the referee on the call its a game that will challenge a childs imagination the work doesnt challenge him anymore and hes often bored noun the next major challenge for the . Synonyms for challenge at thesauruscom with free online thesaurus antonyms and definitions find descriptive alternatives for challenge. Law a formal objection to the qualifications of a particular juror to his or her serving or to the legality of an entire jury compare peremptory challenge. 4 a test of ones abilities or resources in a demanding but stimulating undertaking a career that offers a challenge. Challenge definition 1 the situation of being faced with something that needs great mental or physical effort in order to be done successfully and therefore tests a persons ability 2 an invitation to compete or take part especially in a game or argument 3 an invitation to do something learn more