1. the state of being awake and alert
2. inability to sleep; insomnia

Examples

• The coffee helped maintain her wakefulness during the long drive.
• His wakefulness at night was caused by stress from work.
• The medication can cause wakefulness as a side effect.
• She struggled with chronic wakefulness and sought medical help.
• The baby’s wakefulness kept the parents up all night.
• Bright lights can promote wakefulness in the evening hours.