scum

名词 scum:

1. worthless people
   同义词：trash
2. a film of impurities or vegetation that can form on the surface of a liquid

动词 scum:

1. remove the scum from

1. These scum who fight at the football matches must be severely dealt with!
   必须对那些专在足球比赛时打架的社会渣滓严加惩处！
2. When the meat is boiling, remove the scum.
   当肉煮沸时，把浮在上面的浮渣撇掉。
3. I wouldn't have anything to do with those scum.
   我不会和那些无耻之徒来往。