These criminals are the dregs of society. 这些罪犯都是社会的渣滓。
The dregs have settled at the bottom of the bottle. 渣滓都沉到瓶底了.
The dregs settled and the liquid became clear. 渣滓沉淀下来,液体变清了。
dreg
[ noun ] a small amount of residue <noun.quantity>
Dreg \Dreg\ (dr[e^]g), n. [Prob. from Icel. dregg; akin to Sw. dr["a]gg, cf. Icel. & Sw. draga to draw. Cf. {Draw}.] Corrupt or defiling matter contained in a liquid, or precipitated from it; refuse; feculence; lees; grounds; sediment; hence, the vilest and most worthless part of anything; as, the dregs of society.
We, the dregs and rubbish of mankind. --Dryden.
Note: Used formerly (rarely) in the singular, as by Spenser and Shakespeare, but now chiefly in the plural.