From The Collaborative International Dictionary of English v.0.48 [gcide]:
Wakeful \Wake"ful\, a.
Not sleeping; indisposed to sleep; watchful; vigilant.
[1913 Webster]
Dissembling sleep, but wakeful with the fright.
--Dryden.
[1913 Webster] -- Wake"ful*ly, adv. -- Wake"ful*ness, n.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
wakeful
adj 1: 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" [syn: argus-eyed, open-eyed, vigilant,
wakeful]
2: (of sleep) easily disturbed; "in a light doze"; "a light
sleeper"; "a restless wakeful night" [syn: light,
wakeful]
3: marked by full consciousness or alertness; "worked every
moment of my waking hours" [syn: waking, wakeful]