sleep·​less | \ ˈslēp-ləs How to pronounce sleepless (audio) \

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

Other Words from sleepless

sleeplessly adverb
sleeplessness noun

Examples of sleepless in a Sentence

He lay sleepless in bed.
Recent Examples on the Web Those sleepless nights do a number on Dad's skin, and with the great power of being a dad comes the great responsibility to take care of himself. Amanda Garrity, Good Housekeeping, 15 May 2022 As a new mom, Joy Woodson expected a lot of sleepless nights, to worry every time her baby wouldn’t stop crying and for her heart to leap at her newborn’s slightest smile. Lautaro Grinspan, ajc, 13 May 2022 For many Conservative MPs, that is causing sleepless nights. Luke Mcgee, CNN, 4 May 2022 In terms of finance, interest rates are a prime factor and as transactions are normally in United States Dollars, that should be giving investors and airlines some sleepless nights. David Yu, Forbes, 27 Apr. 2022 Sarah Pinborough knows that sleepless nights can be scary. Calie Schepp,, 21 Apr. 2022 In the lead up to Paul and Dawn's New York meeting, Dawn spent sleepless nights worrying something unexpected would prevent her meeting Paul. Francesca Street, CNN, 24 Mar. 2022 The heavy bags under his eyes looked as if they were relieved to finally rest after so many sleepless nights. Aaron Couch, The Hollywood Reporter, 21 Mar. 2022 Facing the financial strain of covering the rent, her husband spent sleepless nights researching cannabis regulations. Los Angeles Times, 27 Jan. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'sleepless.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of sleepless

15th century, in the meaning defined at sense 1

Buying Guide

Our Reviews team has selected the best sleep masks.

Learn More About sleepless

Time Traveler for sleepless

Time Traveler

The first known use of sleepless was in the 15th century

See more words from the same century

Dictionary Entries Near sleepless

sleeping table


sleep like a baby/log

See More Nearby Entries 

Statistics for sleepless

Last Updated

21 May 2022

Cite this Entry

“Sleepless.” Dictionary, Merriam-Webster, Accessed 24 May. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More Definitions for sleepless


sleep·​less | \ ˈslē-pləs How to pronounce sleepless (audio) \

Medical Definition of sleepless

: not able to sleep : insomniac

Other Words from sleepless

sleeplessness noun

More from Merriam-Webster on sleepless

Nglish: Translation of sleepless for Spanish Speakers

Britannica English: Translation of sleepless for Arabic Speakers


Test Your Vocabulary

Name That Color

  • a light greenish blue color
  • Name that color:
True or False

Test your knowledge - and maybe learn something along the way.

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!