Did you know?

Click any word in a definition or example to find the entry for that word

scum - definition and synonyms

What are red words?

90% of the time, speakers of English use just 7,500 words in speech and writing. These words appear in red, and are graded with stars. One-star words are frequent, two-star words are more frequent, and three-star words are the most frequent.

Thesaurus diagram

The thesaurus of synonyms and related words is fully integrated into the dictionary. Click on the thesaurus category heading under the button in an entry to see the synonyms and related words for that meaning.

noun [uncountable]     scum pronunciation in British English
  1. 1
    a layer of a dirty or unpleasant substance that forms on the surface of a liquid

    A thick layer of black scum lay on the canal water.

    Synonyms and related words
  2. 2
    offensive an insulting word for someone who you think is very unpleasant

    The people who do these dreadful things are scum.

derived word


Word Forms
Synonyms and related words


a rainbow produced when water droplets in the air reflect light from the moon rather than the sun

BuzzWord Article

Open Dictionary

platform capitalism

a way of doing business that involves recruiting large numbers of people who work for themselves using the company's platform, as used by companies such as Uber, Deliveroo and the like

add a word


A must for anyone with an interest in the changing face of language. The Macmillan Dictionary blog explores English as it is spoken around the world today.

global English and language change from our blog
Macmillan learn live love play