“战斗状态”常见的英文表达有 “combat readiness” 或 “battle-ready state”。
combat readiness：更强调为战斗做好准备的状态，在军事语境中较为常用，比如：The troops were maintained at a high level of combat readiness.（部队保持高度战斗准备状态。 ）
battle-ready state：直白地表达出处于可以随时投入战斗的状态 ，例如：The soldiers were in a battle-ready state.（士兵们处于战斗状态。 ）