Scum : nf (word from Norman raze ; from popular Latin rasicare « scrape, to scratch », classic shave).
The word "scum" has several meanings:
Aged meaning: Despicable populace (synonyms: canaille, lie, plebe).
Modern meaning: Set of scoundrels.
Set of unsavory individuals, potential delinquents of a community (suburbs, cities).
A scum: disreputable person.
In verlan: curdled.