Narcoleptic refers to a sleep disorder that causes sudden attacks of deep sleep during the day. The opposite of most narcoleptic would be someone who is highly energized and alert at all times, with no tendency to fall asleep involuntarily. Other antonyms for narcoleptic could be awake, alert, lively, energetic, active, and wide awake. A person who is the antithesis of being narcoleptic would also be highly focused, productive, and mentally sharp. Such individuals would not experience any excessive daytime drowsiness or sudden bouts of sleepiness. Being the exact opposite of narcoleptic would require staying on top of one's physical and mental health, getting enough sleep, and maintaining a healthy lifestyle.