scum

A layer of impurities that accumulates at the surface of a liquid (especially molten metal or water).

During smelting, scum rises to the surface and is then removed by the smelter.

A greenish water vegetation (such as algae), usually found floating on the surface of ponds

These organisms form scum in large quantities.

The topmost liquid layer of a cesspool or septic tank.

Semen.

Horse, who was always talking about facts, said, “Man, that can't be scum, ’cause scum is white.”

A reprehensible person or persons.

People who sell used-up pens are scum, just total low-lives.

To remove the layer of scum from (a liquid etc.).

To remove (something) as scum.

Some scumd the drosse, that from the metall came; / Some stird the molten owre with ladles great[…].

To become covered with scum.

Take the smallest Cucumbers you can get, and as free from Spots as possible, put them into a strong Salt and Water for nine or ten Days, or 'till they are quite Yellow, and stir them twice a Day at least, or they will scum over, and grow soft

To scour (the land, sea, etc.).

SOo by Merlyns aduys ther were sente fore rydars to skumme the Countreye / & they mette with the fore rydars of the north / and made hem to telle whiche wey the hooste cam / and thenne they told it to Arthur / and by kyng Ban and Bors counceill they lete brenne and destroye alle the contrey afore them there they shold ryde

Wandering up and down without certain seat, they lived by scumming those seas and shores as pirates.

To gather together, as scum.

A great majority of the members are scummed together from the Jacobinical dregs of former periods of the revolution.

Acronym of Society for Cutting Up Men.

The most extreme position in the late 1960s came from SCUM, the Society for Cutting Up Men, whose manifesto began, […].