Webster’s Revised Unabridged Dictionary · 1913
Slump
Slump, v. i. 1. To slide or slip on a declivity, so that the motion is perceptible; — said of masses of earth or rock.
2. To undergo a slump, or sudden decline or falling off; as, the stock slumped ten points. [Colloq.]
Slump, n. A falling or declining, esp. suddenly and markedly; a falling off; as, a slump in trade, in prices, etc. [Colloq.]