Waste material from a mine.

Scum that forms on the surface of molten metal.

Impurities formed and separated out when a metal is smelted from ore; vitrified cinders.

Hard aggregate remaining as a residue from blast furnaces, sometimes used as a surfacing material.

Scoria associated with a volcano.

(UK, slang, derogatory) A prostitute or promiscuous woman; a slut.

(UK, derogatory, dated) A coward.

(UK, chiefly Cockney, derogatory) A contemptible person, a scumbag.

(transitive) To produce slag.

(intransitive) To become slag; to agglomerate when heated below the fusion point.

(transitive) To reduce to slag.

(slang, transitive, sometimes with "off") To talk badly about; to malign or denigrate (someone).

(intransitive, Australia, slang) To spit.