noun
guarding; being on guard; watchfulness
Refers to the state or manner of being vigilant, watchful, or on guard, often in a security or protective context.
警察の警戒ぶりが厳しくなった。
The police's guarding became stricter.
彼の警戒ぶりは異常だった。
His watchfulness was unusual.
警戒 is the general noun/verb for 'vigilance' or 'to be on guard'; 警戒ぶり specifically describes the manner or state of that vigilance.
Compound of 警戒 (vigilance, caution) and 振り/ぶり (manner, state).