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Synonyms

slag

1 American  
[slag] / slæg /

noun

  1. Also called cinder.  the more or less completely fused and vitrified matter separated during the reduction of a metal from its ore.

  2. the scoria from a volcano.

  3. waste left over after the re-sorting of coal.


verb (used with object)

slagged, slagging
  1. to convert into slag.

  2. Metallurgy. to remove slag from (a steel bath).

verb (used without object)

slagged, slagging
  1. to form slag; become a slaglike mass.

slag 2 American  
[slag] / slæg /

noun

  1. British Slang. an abusive woman.


slag British  
/ slæɡ /

noun

  1. Also called: cinder.  the fused material formed during the smelting or refining of metals by combining the flux with gangue, impurities in the metal, etc. It usually consists of a mixture of silicates with calcium, phosphorus, sulphur, etc See also basic slag

  2. a mass of rough fragments of pyroclastic rock and cinders derived from a volcanic eruption; scoria

  3. a mixture of shale, clay, coal dust, and other mineral waste produced during coal mining

  4. slang a coarse or dissipated girl or woman

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

verb

  1. slang (tr) (usually foll by off) to abuse (someone) verbally

  2. slang (intr) to spit

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
slag Scientific  
/ slăg /
  1. The vitreous mass left as a residue by the smelting of metallic ore. It consists mostly of the siliceous and aluminous impurities from the iron ore.


Usage

What else does slag mean? Content warning: the following content includes references to strong and sexist language. In slang, slag is an insulting British English term for a contemptible person. When used of women, it can be equivalent to slut. As a verb, to slag (off somebody) is "to attack (them) verbally," i.e., to talk smack about them.

Other Word Forms

Etymology

Origin of slag1

1545–55; < Middle Low German slagge; cognate with German Schlacke dross, slag; see slack 2

Origin of slag2

First recorded in 1780–90; originally an argot word for a worthless person or a thug; perhaps identical with slag 1

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

Copper, steel, aluminum and precious metals can be recovered, but rare-earth metals typically fuse with other byproducts in waste called slag.

From The Wall Street Journal Jan. 23, 2026

He said it also makes steel recycling less polluting because making the chemicals currently used as slag has a high carbon cost too.

From BBC May 22, 2024

"We found the combination of cement clinker and iron oxide is an excellent steelmaking slag because it foams and it flows well," said Dunant.

From Science Daily May 22, 2024

The Cambridge team spotted the composition of used cement is almost exactly the same as the slag used in electric arc furnaces.

From BBC May 22, 2024

In one case the arsenic came from the slag heaps of mining operations, in the other from rock with a high natural content of arsenic.

From "Silent Spring" by Rachel Carson

Lieberstein previously worked on "The Office" as one of its producers and as Toby, the bland HR representative everyone slagged off on.

From Salon Mar. 19, 2023

Executives who didn’t take her calls risked being slagged on Deadline.

From New York Times Jan. 21, 2023

"Anyone that we haven't slagged off," jokes Mica.

From BBC May 8, 2022

Anyway, you’ll be happy to hear, I fought through my misgivings and slagged the performance—but it struck me that if I was thinking about these questions in this context, these questions have permeated very deep.

From Slate Dec. 19, 2018

Hardly big enough so a cat could slip through, and under it is this big pile of coal slagged up against the foundation wall.

From "Freak The Mighty" by Rodman Philbrick

He said: "No, we read Vanity Fair - they're slagging each other off in the pages... You don't need to go for lunch with those people."

From BBC May 26, 2023

“This is not about slagging anyone off in this TV series at all,” he said.

From Seattle Times Jul. 16, 2021

Fearn doesn’t share the inclination, saying, “I’ve never really been into slagging bands off. It’s just not my thing.”

From Washington Post Jan. 21, 2021

YouTube videos were dedicated to slagging her off.

From The Guardian Nov. 16, 2020

Gary Drake and Ross Wilcox might’ve been slagging me off, but the fainter the voices became, the less I wanted to go back.

From "Black Swan Green" by David Mitchell

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