- 1slump (in something) a sudden fall in sales, prices, the value of something, etc. synonym decline a slump in profits This is the worst slump in property prices since the 1990s.
- 2a period when a country's economy or a business is doing very badly the slump of the 1930s Housing sales are finally coming out of a three-month slump. The toy industry is in a slump. compare boom