(uncountable) A layer of impurities that accumulates at the surface of a liquid (especially molten metal or water).
(uncountable) A greenish water vegetation (such as algae), usually found floating on the surface of ponds
The topmost liquid layer of a cesspool or septic tank.
(uncountable, slang, chiefly US) semen
(countable, derogatory, slang) A reprehensible person or persons.
(countable, derogatory, slang) police officer(s)
* (layer of impurities) dross, impurities
* (layer of impurities on molten metal) cinder, scoriae, slag
* (person considered reprehensible) bastard
To remove the layer of scum from (a liquid etc.).
To remove (something) as scum.
*1590 , Edmund Spenser, The Faerie Queene , II.vii:
*:Some scumd the drosse, that from the metall came; / Some stird the molten owre with ladles great.
To become covered with scum.
*1769 , Elizabeth Raffald, The Experienced English House-keeper , pp.321-322:
*: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
(obsolete) 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.
(obsolete) To gather together, as scum.
*1815 , Rudolf Ackerman and Frederic Shoberl, The Repository of Arts, Literature, Commerce, Manufactures, Fashions and Politics :
*:A great majority of the members are scummed together from the Jacobinical dregs of former periods of the revolution.
To startscum or savescum.