"Big slump" refers to a significant decline or drop in performance, productivity, or success in someone or something. It means that there has been a noticeable decrease in progress or achievements. Full definition
Treasury Secretary Steven Mnuchin warned that failure to pass those bills would trigger a big slump. (canadianbusiness.com)
Analysts at Goldman Sachs continue to recommend owning commodities even though the asset class continues to suffer from the biggest slump in eight months. (benzinga.com)
Arsenal are currently in the biggest slump I have ever known under Arsene Wenger, and although the Gunners lost four games in a row in 2002, they have never lost five in a row under the Boss, which could easily happen on Thursday. (justarsenal.com)