• n. 浮渣；泡沫；糟粕
• vi. 产生泡沫；被浮渣覆盖
• vt. 将浮渣去除掉

来自中古英语 scum,泡沫，浮渣，来自 Proto-Germanic*skumaz,覆盖，隐藏，来自 PIE*skeu, 覆盖，隐藏，词源同 hide,skim.引申比喻义渣滓，败类等。

scum

scum: [13] Scum is etymologically a ‘layer on top’ of something. The word’s modern connotations of ‘dirt’ are a secondary development. It comes ultimately from prehistoric Germanic *skūman, a derivative of the base *skū- ‘cover’, and its relatives include German schaum ‘foam’ (source of English meerschaum [18], literally ‘sea-foam’).

English scum originally meant ‘foam’ too (‘Those small white Fish to Venus consecrated, though without Venus’ aid they be created of th’ Ocean scum’, Joshua Sylvester, Divine Weeks and Works of Du Bartas 1598), the notion being of a layer of froth ‘covering’ liquid, but by the 15th century it was broadening out to any ‘film on top of liquid’, and from there it went downhill to a ‘film of dirt’ and then simply ‘dirt’.

Germanic *skūman was borrowed into Old French as escume, and this formed the basis of a verb escumer ‘remove the top layer’, from which English gets skim [15].
=> meerschaum, skim

scum (n.)

early 14c. (implied in scummer "shallow ladle for removing scum"), from Middle Dutch schume "foam, froth," from Proto-Germanic *skuma- (cognates: Old Norse skum, Old High German scum, German Schaum "foam, froth"), perhaps from PIE root *(s)keu- "to cover, conceal" (see hide (n.1)).

Sense deteriorated from "thin layer atop liquid" to "film of dirt," then just "dirt." Meaning "lowest class of humanity" is 1580s; scum of the Earth is from 1712. Adopted in Romanic (Old French escume, Modern French écume, Spanish escuma, Italian schiuma).

1. Someone had scrawled "Scum" on his car.

有人在他的车上涂写了“人渣”的字样。

来自柯林斯例句

2. Skim off any scum.

撇净浮沫。

来自《权威词典》

3. Skim the scum off the jam and let it cool.

撇去果酱上的浮沫，让它冷却。

来自《权威词典》

4. There is a ring of scum in the washbasin.

这个脸盆内有一圈污垢.

来自《简明英汉词典》

5. There was green scum over the pond.

池塘水面有绿色的浮藻.

来自《简明英汉词典》