n. & v.
n. 1 a sudden severe or prolonged fall in prices or values of commodities or securities. 2 a sharp or sudden decline in trade or business usu. bringing widespread unemployment. 3 a lessening of interest or commitment in a subject or undertaking.
v.intr. 1 undergo a slump; fail; fall in price. 2 sit or fall heavily or limply (slumped into a chair). 3 lean or subside.
[ 17th c., orig. 'sink in a bog': imit. ]