Wakefulness is a condition of being alert, rather than sleepy. Last night's wakefulness might catch up with you later and make it hard to keep your eyes open during chemistry class.

A new baby's wakefulness, keeping them wide awake all night, usually results in exhausted parents. You can also use this noun for a kind of vigilance or alertness, sort of a figurative way of being awake: "The teacher's wakefulness meant that she noticed immediately if a student was falling behind or being bullied." The original meaning of wakeful, in fact, was "diligent," from an Old English root meaning "night watch."

Definitions of wakefulness

n a periodic state during which you are conscious and aware of the world

“consciousness during wakefulness in a sane person is pretty well ordered and familiar”
awakening from sleep
a period of sleeplessness
Type of:
the state of remaining awake
physical condition, physiological condition, physiological state
the condition or state of the body or bodily functions

n the process of paying close and continuous attention

wakefulness, watchfulness, and bellicosity make a good hunter”
alertness, vigilance, watchfulness
zealous vigilance
Type of:
the faculty or power of mental concentration

n 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”
drowsiness, sleepiness, somnolence
a very sleepy state
Type of:
temporary state
a state that continues for a limited time

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