The Oxford Thesaurus An A-Z Dictionary of Synonyms - slump n.

1) dip, trough, depreciation, decline, downturn, downslide, recession, depression, falling-off, fall-off, fall, drop, plunge, descent, crash, collapse, failure; nosedive, tailspin: A slump in the housing market was one of the early signs of the impending recession. The market went into a slump this morning from which it barely recovered before closing. --v. 2) decline, slip, recede, fall (off) , drop, plunge, descend, sink, crash, collapse, dive, plummet, take or go into a nosedive or tailspin: Prices on the stock market slumped following announcement of a rise in interest rates. 3) See slouch, 1, above.