This is the 1088th most frequent Russian word.
противовоздушной
Anti-aircraft.
Here, 'противовоздушной' serves as an adjective modifying 'техникой' (equipment), specifying its nature being related to countering air attacks.
Мы обучались управлению противовоздушной техникой на специальном полигоне.
We trained in operating anti-aircraft equipment at a special range.
In this context, 'противовоздушной' describes 'обороны' (defense), characterizing it as aimed against aerial threats and attacks.
Эффективность противовоздушной обороны оценивается после каждого учения.
The effectiveness of the anti-air defense is assessed after each exercise.
Here, 'противовоздушные' is used as an adjective to describe 'системы' (systems), indicating their purpose for countering or defending against aerial threats.