wakeful

adjectives

carefully observant or attentive; on the lookout for possible danger
"a policy of open-eyed awareness"; "the vigilant eye of the town watch"; "there was a watchful dignity in the room"; "a watchful parent with a toddler in tow"
argus-eyed, open-eyed, vigilant, wakeful
is derived from
wakefulness
(of sleep) easily disturbed
"in a light doze"; "a light sleeper"; "a restless wakeful night"
light, wakeful
is derived from
wakefulness
marked by full consciousness or alertness
"worked every moment of my waking hours"
wakeful, waking