Simple Definition of sleepless
: without sleep
: not able to sleep
Full Definition of sleepless
1 : not able to sleep <lay sleepless with fever>
2 : affording no sleep <sleepless nights>
3 : unceasingly active or operative <sleepless casinos>
Examples of sleepless
He lay sleepless in bed.
First Known Use of sleepless
Seen and Heard
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