1. 作战：Losing battle 必败之战 | Military operation 作战 | Missile equipped destroyer 导弹驱逐舰

2. 军事行动：军事任务military mission | 军事行动military operation | 军事武器military weapon

3. 軍事作業;軍事作戰：military missions 軍事任務 | military operation 軍事作業;軍事作戰 | military qualification test 軍用合格測驗

4. 军事操作：military assignment 军用频率指配 | military operation 军事操作 | millennium bug 电脑公元二千年数位问题/千年虫

noun

1. activity by a military or naval force (as a maneuver or campaign)

e.g. it was a joint operation of the navy and air force

Synonym: operation