Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “sleepless”

sleepless

adjective [not gradable]  /ˈslip·ləs/ us  
without sleeping, or without being able to sleep: I’ve spent so many sleepless nights worrying about him.
(Definition of sleepless from the Cambridge Academic Content Dictionary © Cambridge University Press)
What is the pronunciation of sleepless?
Add Cambridge dictionaries to your browser to your website

Definitions of “sleepless” in other dictionaries

Word of the Day

roost

When birds roost, they go somewhere to rest or sleep.

Word of the Day

Blog

Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More