SCUM

I. noun Etymology: Middle English, from Middle Dutch schum; akin to Old High German scūm foam Date: 14th century 1. extraneous matter or impurities risen to or formed on the surface of a liquid often as a foul filmy covering, the scoria of metals in a molten state ; dross , a slimy film on a solid or gelatinous object, 2. refuse , a low, vile, or worthless person or group of people, ~my adjective II. intransitive verb (~med; ~ming) Date: 1661 to become covered with or as if with ~