Scum (skŭm), n. [Of Scand. origin; cf. Dan. & Sw. skum, Icel. skūm, LG. schum, D. schuim, OHG. scūm, G. schaum; probably from a root meaning, to cover. √158. Cf. Hide skin, Meerschaum, Skim, v., Sky.]
1. The extraneous matter or impurities which rise to the surface of liquids in boiling or fermentation, or which form on the surface by other means; also, the scoria of metals in a molten state; dross.
Some to remove the scum as it did rise. Spenser.
2. refuse; recrement; anything vile or worthless.
The great and innocent are insulted by the scum and refuse of the people. Addison.