A more thorough explanation:

Definition: Something that is onerous is very difficult or causes a lot of problems.

Examples:

• Studying for the final exams was an onerous task for the students.
• The new job came with onerous responsibilities that made it hard for the employee to balance work and personal life.
• The contract had onerous terms that made it difficult for the company to make a profit.

The examples illustrate that onerous refers to something that is burdensome, troublesome, or involves obligations that outweigh the advantages. It can be used to describe tasks, responsibilities, or contracts that are difficult to manage or fulfill.