undertaking
n. countablen. a job, task, or project that is usually big, difficult, or important. You use this word when you want to show that a piece of work requires a lot of effort.
n. a task, project, or enterprise, especially one that is particularly large or demanding. Often implies a formal commitment or a significant investment of resources.
Building a new house is a massive undertaking.
The restoration of the historic cathedral proved to be a costly and time-consuming undertaking for the city.
Launching a satellite into orbit is a complex undertaking that requires the seamless coordination of thousands of engineers and scientists across multiple continents.
By surface analysis, undertake + -ing.
Commonly paired with adjectives like 'massive', 'major', or 'serious' to emphasize the scale of the task.