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
But the residue would find its way into my sleepless nights.
—
Literary Hub, 17 Sep. 2025
Leaders who normalize overwork, skipped lunches and sleepless nights unintentionally create cultures of burnout.
—Bydr. Marita Kinney, Forbes.com, 16 Sep. 2025
Jaonaay spent three to four months with producer Karn of Yented crafting the modern R&B track, which captures the sleepless nights and racing thoughts of new love.
—Naman Ramachandran, Variety, 12 Sep. 2025
What happened next has caused Cadrez multiple sleepless nights.
—Troy Renck, Denver Post, 1 Sep. 2025
See All Example Sentences for sleepless
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Literary Hub, 17 Sep. 2025
Leaders who normalize overwork, skipped lunches and sleepless nights unintentionally create cultures of burnout.
—Bydr. Marita Kinney, Forbes.com, 16 Sep. 2025
Jaonaay spent three to four months with producer Karn of Yented crafting the modern R&B track, which captures the sleepless nights and racing thoughts of new love.
—Naman Ramachandran, Variety, 12 Sep. 2025
What happened next has caused Cadrez multiple sleepless nights.
—Troy Renck, Denver Post, 1 Sep. 2025
See All Example Sentences for sleepless
Cite this Entry
“Sleepless.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/sleepless. Accessed 26 Sep. 2025.
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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