Wakeful is an adjective meaning "unable or not wanting to sleep; alert and watchful". Historically, it is from wake (Old English wacian/wacan 'to be awake, arise', from Proto-Germanic *wakaną) plus the adjective-forming suffix -ful. The visible construction is part of the etymology: wakeful is not just an unanalyzed simple word. The modern meaning, "unable or not wanting to sleep; alert and watchful", follows the base word through the added English ending. The historical chain links Old English wacian, Proto-Germanic *wakaną, and Proto-Indo-European *weǵ-. Close English family members include wakefully, wakefulness, wake, waken, and awake.