风吹草动（風吹草動）　

◎ 风吹草动 fēngchuī-cǎodòng

[the slightest sign of disturbance;at the mere rustle of leaves in the wind;be sensitive to the slightest upset as the grass bends whenever the wind blows] 有风吹,草就动。喻指因轻微的动作而发生影响

万一有些风吹草动,不要我管门起来,赶得出去,就是个死。——《二刻拍案惊奇》