A respectable London daily has this headline: How the (name of another paper) makes serialisation pay. First, you buy the memoirs , then you slag them off." The deck (subhead) continues: (Name of woman celebrity whose memoirs are being serialized by X newspaper) is just the latest victim of a cost-effective strategy. Could someone please tell me what the verb "slag them off" means in that context? Does it mean something like "to criticize"? Thank you.