a. [ L. vigilans, -antis, p. pr. of vigilare to watch, fr. vigil awake: cf. F. vigilant. See Vigil. ] Attentive to discover and avoid danger, or to provide for safety; wakeful; watchful; circumspect; wary. “Be sober, be vigilant.” 1 Pet. v. 8. [ 1913 Webster ]
Sirs, take your places, and be vigilant. Shak. [ 1913 Webster ]
adv. In a vigilant manner. [ 1913 Webster ]