an unstable construction with playing cards; "he built three levels of his cardcastle before it collapsed"
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"
become broader or wider or more extensive; "The road widened"
make wider; "widen the road"
extend in scope or range or area; "The law was extended to all citizens"; "widen the range of applications"; "broaden your horizon"; "Extend your backyard"
without a basis in reason or fact; "baseless gossip"; "the allegations proved groundless"; "idle fears"; "unfounded suspicions"; "unwarranted jealousy"