vigilant
adjective uk/ˈvɪdʒ.əl.ənt/ us/ˈvɪdʒ.əl.ənt/
警觉的；警戒的；警惕的
always being careful to notice things, especially possible danger
Following the bomb scare at the airport, the staff have been warned to be extra vigilant. 机场的炸弹恐吓事件之后，全体员工都被告诫要格外警惕。
Synonyms: open-eyedwatchful