[n] a noticeable decline in performance; "the team went into a slump"; "a sudden slack in output"; "a drop-off in attendance"; "a falloff in automobile sales"
[n] a long-term economic state characterized by unemployment and low prices and low levels of trade and investment
[v] fall heavily or suddenly; decline markedly; "The real estate market fell off"
[v] fall or sink heavily; "He slumped onto the couch"; "My spirits sank"
[v] assume a drooping posture or carriage