on toes

anxious attentive aware cautious circumspect keen observant wary

acute agog alert guarded looking for looking to on alert on guard on the ball on the job on the lookout on the qui vive 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