表达思想和观点

1. (任务或工作)艰巨的，具有挑战性的，要求高的
A challenging task or job requires great effort and determination.

2. 挑战性的;挑衅的
If you do something in a challenging way, you seem to be inviting people to argue with you or compete against you in some way.

1. requiring full use of your abilities or resources

e.g. ambitious schedule
performed the most challenging task without a mistake

Synonym: ambitious

2. disturbingly provocative

e.g. an intriguing smile

Synonym: intriguing

3. stimulating interest or thought

e.g. a challenging hypothesis
a thought-provoking book

Synonym: thought-provoking