Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “scum”


noun [U]  /skʌm/ us  
a thin layer that forms on the surface of a liquid: The tea was nasty-tasting stuff that looked like pond scum. I wish you wouldn’t leave soap scum in the bathtub.
(Definition of scum from the Cambridge Academic Content Dictionary © Cambridge University Press)
What is the pronunciation of scum?
Add Cambridge dictionaries to your browser to your website

Definitions of “scum” in other dictionaries

Word of the Day


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

Word of the Day


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