concealing crafty designs for advancing your own interest; "a selfish and designing nation obsessed with the dark schemes of European intrigue"- W.Churchill; "a scheming wife"; "a scheming gold digger"
a noticeable deterioration in performance or quality; "the team went into a slump"; "a gradual slack in output"; "a drop-off in attendance"; "a falloff in quality"
fall heavily or suddenly; decline markedly; "The real estate market fell off"
fall or sink heavily; "He slumped onto the couch"; "My spirits sank"