From Longman Dictionary of Contemporary Englishscumscum /skʌm/ noun 1 [uncountable]LIQUID an unpleasant dirty substance that forms on the surface of water a pond covered with green scum2 [plural] informalBAD PERSON nasty unpleasant people Scum like that should be locked away! People like that are the scum of the earth. —scummy adjective
Examples from the Corpus
scum• Reduce heat and simmer slowly, uncovered, for 2 to 3 hours, skimming any scum that rises to surface.• This was a brown, evil-looking brew, topped by grey scum, with the taste and texture of fine silt.• See Igor slowly realize his dad is scum.• Why are cigar smokers cool and cigarette smokers scum?• soap scum on the bathtub• I don't want that scum coming back into my restaurant!• I see that the scum will be the live match in the next round of the cup, what a suprise.• Where scum settles on wetted surfaces in kitchens, it creates an ideal breeding ground for bacteria.the scum of the earth• You are lower than the scum of the earth.• It's open to the scum of the earth.Origin scum (1300-1400) Middle Dutch schum 