mission-critical
adjective uk/ˌmɪʃ.ənˈkrɪt.ɪ.kəl/ us/ˌmɪʃ.ənˈkrɪt̬.ɪ.kəl/
（对公司或活动等）极其重要的，必须的
extremely important or necessary for a company, activity, etc. to operate successfully
mission-critical applications/systems/software 极其关键的应用／系统／软件