something that needs great mental or physical effort in order to be done successfully and therefore tests a person's ability
Finding a solution to this problem is one of the greatest challenges faced by scientists today.
You know me - I like a challenge.
Writing a novel proved to be a significant challenge for the aspiring author, testing both creativity and perseverance.
Completing a marathon is a formidable physical challenge that many athletes train for months to conquer.
Solving the complex mathematical problem posed a serious challenge for the students, requiring deep analytical thinking.
Designing and executing a successful marketing campaign can be a challenging task, demanding strategic planning and innovation.
