What is the meaning of gruelling?

The word "gruelling" is an adjective that means extremely tiring, demanding, or difficult. It can be used to describe a physical or mental challenge that requires a lot of effort and can be exhausting. For example, a gruelling hike up a mountain or a gruelling exam that tests a person's knowledge and endurance. The word "gruelling" often implies a sense of struggle or difficulty that one has to overcome in order to complete the task or challenge.