“江里无风三尺浪”是什么意思？

无风三尺浪；wú fēng sān chǐ làng；【解释】比喻无缘无故也会生出事来。；【结构】复句式成语；【用法】作宾语、分句；指无事生非；【近义词】无事生非、无风起浪；【例句】这真是无风三尺浪；【英译】There are billows three feet high even if there is no wind.