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