1
: not able to sleep
lay sleepless with fever
2
: affording no sleep
sleepless nights
3
: unceasingly active or operative
sleepless casinos
sleeplessly
adverb
sleeplessness
noun
Examples of sleepless in a Sentence
He lay sleepless in bed.
Recent Examples on the Web
Fatigue, severe pain, heavy and irregular flow , sleepless nights on the bathroom floor .
—
Francie Ebert, NBC news, 14 May 2026
Fatigue, severe pain, heavy and irregular flow, sleepless nights on the bathroom floor.
—Kayla Grant, PEOPLE, 14 May 2026
There were sleepless nights of laughter and love-making.
—Emily Bryn Williams, Los Angeles Times, 8 May 2026
Losing a semi-final is supposed to provoke sleepless nights.
—Sebastian Stafford-Bloor, New York Times, 7 May 2026
See All Example Sentences for sleepless
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Francie Ebert, NBC news, 14 May 2026
Fatigue, severe pain, heavy and irregular flow, sleepless nights on the bathroom floor.
—Kayla Grant, PEOPLE, 14 May 2026
There were sleepless nights of laughter and love-making.
—Emily Bryn Williams, Los Angeles Times, 8 May 2026
Losing a semi-final is supposed to provoke sleepless nights.
—Sebastian Stafford-Bloor, New York Times, 7 May 2026
See All Example Sentences for sleepless
Cite this Entry
“Sleepless.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/sleepless. Accessed 16 May. 2026.
Copy CitationKids Definition
sleepless
adjective
sleep·less
ˈslē-pləs 
1
: not able to sleep
2
: marked by the absence of sleep
a sleepless night
3
: unceasingly alert or active
sleeplessly
adverb
sleeplessness
noun
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