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.
intelligence test, first published 1916 as a revision and extension of the Binet-Simon intelligence tests, from Stanford University (California, U.S.) + the name of French psychologist Alfred Binet, who devised the attempt at a scientific measurement of intelligence.