This is the 2153rd most frequent Russian word.
боевое
"Боевое" means "combat" or "battle" in English.
Here, 'боевое' describes the nature of the mission being related to combat or warfare.
У солдата было боевое задание.
The soldier had a combat mission.
In this sentence, 'боевые' modifies 'действия' to describe actions related to military activities.
Боевые действия продолжались всю ночь.
Combat operations continued throughout the night.
Here, 'боевой' is used in a figurative sense to describe someone reliable and supportive, akin to a comrade in combat.