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REFERENCE

scum

n. · v.
US //ˈskəm// UK //skˈʌm// scum
  1. 1 surface dirt (n.)
    B2 Upper Intermediate

    a layer of dirt, bubbles, or waste that forms on the surface of a liquid like water or soup.

    a layer of impurities, organic matter, or chemical waste that accumulates at the surface of a liquid.

    Example

    A thick green scum had formed on the surface of the abandoned pond.

    Example

    The industrial runoff resulted in a greyish scum coating the riverbanks, alarming local environmentalists about the water quality.
  2. 2 insult for people (n.)
    C1 Advanced Informal Slang Vulgar

    a very rude word for people you think are bad, dishonest, or have no morals.

    a highly derogatory collective or singular noun for individuals perceived as worthless, contemptible, or morally bankrupt.

    Example

    He called the people who stole from the charity 'absolute scum'.

    Example

    The tabloid press frequently refers to violent criminals as the scum of the earth to incite public indignation.

    Usage

    Often used as a collective noun without an 's' to refer to a group of people.

    Teacher's tip

    This is a very strong and aggressive insult; students should be aware of its severity and generally avoid using it themselves.
  3. 3 to remove surface dirt (v.)
    C2 Proficiency Technical Cooking

    to take the layer of dirt or waste off the top of a liquid.

    to remove the layer of impurities or froth from the surface of a liquid, such as molten metal or a cooking stock.

    Example

    The chef told his assistant to scum the boiling soup to keep the broth clear.

    Example

    In traditional metallurgy, the technician must carefully scum the molten lead to ensure the final casting is free of structural defects.

    Usage

    In modern cooking, 'skim' is much more common than 'scum'.
Origin

From Middle English scum, scome, skum, skome, scumme, from Middle Low German or Middle Dutch schūme (“foam”), from Old Dutch scūm, from Frankish skūm, from Proto-Germanic skūmaz (“froth, foam”), from Proto-Indo-European (s)kewH- (“to cover, conceal”). Cognate with Dutch schuim (“foam”), West Frisian skuum, German Schaum (“foam”), Danish and Swedish skum (“foam”). Compare also French écume (“scum”), Italian schiuma (“foam”), Saterland Frisian Skuum, Sicilian scuma (“foam”), Walloon schome (“scum, foam”), Lithuanian šamas (“catfish”) and skanus (“tasty”) from the same Germanic source. Related to skim.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Idioms1 entry

Last updated June 20, 2026