Not long ago, John Timpane, the uncredited gossip columnist of my local Philadelphia Inquirer, noted that Sandra Bullock “reported getting slagged all over the Internet for being – over 40. How dare she?”
The Oxford English Dictionary defines the transitive verb “slag” as “To abuse or denigrate (a person); to criticize, insult”; following it with the word “off” is optional. The term dates only from the early ’70s, the OED’s first citations being Jamie Mandelkau, the manager of the rock band The Deviants, in 1971 (“He was doing a good job of bad mouthing and slagging me to a number of the Angels”), and The Guardian in 1972, which provided a helpful etymological note: “Mr Jack Jones, general secretary of the Transport and General Workers’ Union, was ‘slagged off’—in dockland jargon—several times during the day.”
All the OED citations are from British sources, and the term is still far more common on that side of the pond, but it has been making inroads as a NOOB at least since 2007, when Virginia Heffernan wrote in the New York Times (about online culture): “I’ve sat idly by while regular posters slagged off shows or people I like.”
Referring as it does to the waste products of smelting metal, “slag” is a vivid word, and can be effective in an American context, where it’s still a relative novelty. Thus Richard Aregood, also writing in the (NY) Times, about a press conference from Chris Christie, the governor of New Jersey:
He said he had just learned what everybody in the state had suspected for weeks — that his own people had created a traffic nightmare in Fort Lee to get back at its Democratic mayor. Then he slagged his own people and called them names. Then he wallowed in self-pity for the way they had betrayed him.