Antonyms of noun sleepiness

1 sense of sleepiness

Sense 1
sleepiness, drowsiness, somnolence -- (a very sleepy state; "sleepiness causes many driving accidents")
       Antonym of wakefulness (Sense 2)
      => wakefulness, sleeplessness -- (a temporary state in which you are unable (or unwilling) to sleep; "accept your wakefulness and sleep in its own contrary way is more likely to come")

Synonyms/Hypernyms (Ordered by Estimated Frequency) of noun sleepiness

1 sense of sleepiness

Sense 1
sleepiness, drowsiness, somnolence -- (a very sleepy state; "sleepiness causes many driving accidents")
       => temporary state -- (a state that continues for a limited time)