slag

Short definition from Wiktionary

Noun

1. 1
   Waste material from a mine.
2. 2
   Scum that forms on the surface of molten metal.
3. 3
   Impurities formed and separated out when a metal is smelted from ore; vitrified cinders.
4. 4
   Hard aggregate remaining as a residue from blast furnaces, sometimes used as a surfacing material.
5. 5
   Scoria associated with a volcano.
6. 6
   A prostitute or promiscuous woman; a slut.
7. 7
   A coward.
8. 8
   A contemptible person, a scumbag.

Verb

1. 1
   To produce slag.
2. 2
   To become slag; to agglomerate when heated below the fusion point.
3. 3
   To reduce to slag.
4. 4
   To talk badly about; to malign or denigrate (someone).
5. 5
   To make fun of; to take the piss (tease, ridicule or mock).
6. 6
   To spit.