This is the 4232nd most frequent Japanese word.
任務
Duty; mission; task.
In this sentence, '任務' refers to assigned responsibilities or tasks that one is obligated to accomplish.
彼は任務を果たすために毎日努力しています。
He puts in effort every day to fulfill his duties.
Here, '任務' indicates a specific mission or operation that requires efforts to achieve.
その任務は難しいが、チームの協力で成功した。
The mission was challenging, but it was successful through teamwork.
In this usage, '任務' represents an assignment or task that someone has been given responsibility for.