vigilant adj.
VERBS be, keep, remain, stay | become
ADV. especially, extra, extremely, particularly, very | constantly, ever The organization is ever vigilant for threats to the habitats of birds.
PREP. about Be extra vigilant about what you eat or drink. | against You need to be vigilant against garden pests.
You can also check other dicts: vigilant (English, 中文解释 ), wordnet sense, Collins Definition