Source : Webster's Revised Unabridged Dictionary (1913)

Wakeful \Wake"ful\, a.
   Not sleeping; indisposed to sleep; watchful; vigilant.

         Dissembling sleep, but wakeful with the fright.
                                                  --Dryden.
   -- {Wake"ful*ly}, adv. -- {Wake"ful*ness}, n.