on alert

accessible at hand at one's beck and call at one's disposal at one's fingertip available handy night call on deck on-the-spot prepared standing by within reach

anxious attentive aware cautious circumspect keen observant wary

acute agog alert guarded looking for looking to on guard on the ball on the job on the lookout on the qui vive on toes open-eyed sharp sleepless unsleeping waiting on wakeful wide-awake with eyes peeled with weather eye open

careless heedless ignorant inattentive incautious indifferent indiscreet rash thoughtless unaware uncareful unobservant

impulsive negligent