scum

Scum is a term with multiple, related meanings. In scientific and culinary contexts, it denotes a frothy or floating layer of impurities on a liquid's surface. This scum often consists of fats, proteins, sugars, and other particles that rise during heating, fermentation, or chemical reactions. It can appear on stock, tea, coffee, beer, or water and is usually skimmed or removed to improve clarity, flavor, or process efficiency. In industrial settings, a scum layer may also refer to surface deposits collected from wastewater or chemical processes.

As a slang term, scum is a highly pejorative label for people judged as morally corrupt, disreputable, or exploitative. It is used to insult or demean individuals or groups and is considered offensive in most contexts. The degree of offensiveness and acceptability varies by culture and situation; in formal writing it is typically avoided, and care should be taken to avoid targeting protected characteristics with pejorative terms.

In literature and media, "scum" is sometimes used metaphorically to critique social conditions or moral decline, as in phrases such as "the scum of society." While its literal and figurative uses share a sense of impurity or degradation, the term remains a strong, value-laden descriptor and should be used with awareness of its impact.