A flimsy structure, arrangement, or situation that is in danger of collapsing or failing: "The collapse of the rupiah... has brought down a house of cards in overleveraged conglomerates" (Sander Thoenes). a plan that is so badly arranged that it is likely to fail
a speculative scheme that depends on unstable factors that the planner cannot control; "his proposal was nothing but a house of cards"; "a real estate bubble