Slump
late 17th century (in the sense ‘fall into a bog’): probably imitative and related to Norwegian slumpe ‘to fall’.
wiktionary
Probably of North Germanic origin: compare Danish slumpe(“to stumble upon by chance”), Norwegian slumpe(“happen by chance”), Swedish slumpa(“to sell off”). Compare also German schlumpen(“to trail; draggle; be sloppy”).
etymonline
slump (v.)
1670s, "fall or sink into a muddy place," probably from a Scandinavian source such as Norwegian and Danish slumpe "fall upon," Swedish slumpa; perhaps ultimately of imitative origin. Related: Slumped; slumping.
The word "slump," or "slumped," has too coarse a sound to be used by a lady. [Eliza Leslie, "Miss Leslie's Behaviour Book," Philadelphia, 1839]
Economic sense from 1888.
slump (n.)
"act of slumping, slumping movement," 1850; "heavy decline in prices on the stock exchange," 1888, from slump (v.). Generalized by 1922 to "sharp decline in trade or business."
