Merriam-Webster's Collegiate® Dictionary, 11th Edition
SLUMP
I. intransitive verb
Etymology: probably imitative
Date: circa 1677
1. to fall or sink suddenly, to drop or slide down suddenly ; collapse , to assume a drooping posture or carriage ; slouch , to go into a slump ,
II. noun
Date: 1887
1. a marked or sustained decline especially in economic activity or prices , a period of poor or losing play by a team or individual , a downward slide of a mass of rock or land